As Ukraine continues to wage a surprisingly successful resistance against Russia, Ukrainian civilians and volunteers are playing a crucial role in defending their county — one for which they have been preparing for the past eight years, since the last major Russian incursion in 2014.

Many civilians are taking up arms themselves, and the Ukrainian government has begun sharing bomb-making instructions and encouraging civilians to take down street signs “in order to confuse and disorient the enemy.”

In a video posted on Friday, Ukrainian President Volodymyr Zelensky confirmed that he and his government were still in Kyiv, with the people of Ukraine, and called for everyone able to take up arms to defend the country — even Ukrainians abroad and foreigners.

It’s all part of a country-wide mobilization built on the back of the volunteer movement that fought against Russian forces in Crimea starting in 2014. Many of those same volunteers — and thousands more like them — are now stepping up to defend against a full-scale Russian invasion.

The readiness of Ukraine’s professional military has significantly improved since the Russian annexation of Crimea in 2014, but “Ukraine is not a rich country,” Andrew D’Anieri, the assistant director of the Atlantic Council’s Eurasia Center, points out. Civilian support, he said, is necessary for the military’s success.

“[Ukraine has] made great strides around better equipping its military, modernizing, but it’s pretty obvious they still do need this kind of crowdfunded support for things like night-vision goggles for soldiers and other kinds of high-tech equipment,” D’Anieri said. “I think it’s a really unique and kind of impressive aspect of how Ukraine has responded to eight years of war.”

That preparedness is on full display now: Many Ukrainians have volunteered to serve with the armed forces, and the Ukrainian Territorial Defense Forces (TDF) — an organized, civilian guard that fights to protect individual cities — are integrating as a formal part of the Ukrainian Armed Forces. And while the assistance of Western nations, in terms of providing weapons and training, has been critical, there are also civil society organizations — like Phoenix Wings and Come Back Alive — which were organized in the 2014 conflict and have mobilized into service now, collecting and delivering supplies like thermal imagers, body armor, and first aid kits to fighters.

Volunteers help support current military infrastructure

The current Ukrainian response only highlights how much the country has changed in eight years, former Ukrainian economy minister Tymofiy Mylovanov told Vox on Thursday.

In 2014, “a lot of people defected [to Russia], the leadership defected, we didn’t have [a] military,” he said. Now, Ukraine has a professionalized military — many of whom previously served in the volunteer forces fighting in eastern Ukraine in 2014. “A lot of people who were volunteers in the frontlines, then, they’ve become battle commanders by now,” he said. “So they are the institutionalized military now.”

Volunteers are also heading to the TDF, the urban battalions trained to defend Ukrainian cities. The Ukrainian government opted to make the TDF part of the Armed Forces starting this year, and according to Kyiv Independent reporter Illia Ponomarenko, the Ukrainian defense ministry expects 11,000 volunteers to sign up this year.

TDF units are supposed to “ensure security and order behind the frontline, assist the Armed Forces in combat operations, guard key infrastructure facilities, and render assistance in combating hostile subversive activities in their local areas,” Ponomarenko reports.

TDF units are made up of military veterans and ordinary civilians — adults of all ages and backgrounds, men and women — who keep their day jobs and train for combat on weekends or otherwise periodically. Leaders, including former television host and now chairman of Ukraine’s Reservists Council Anton Goloborodko, have been building up the force and training civilian recruits to support the armed forces. Although there have been several attempts over the years to formalize the forces, that finally happened when Ukraine’s National Resistance act took effect earlier this year.

Less formal methods of civilian resistance are spreading, too

Now that the invasion has started in earnest, much less formal methods to stave off Russian forces, particularly in urban areas, have been circulating, too — including instructions for homemade weapons.

On Saturday, the Ukrainian-language Twitter account of the National Security and Defense Council of Ukraine tweeted instructions for making Molotov cocktails — bombs made of glass bottles, a flammable substance, and a cloth fuse, which is lit before the improvised device is thrown at a target.

In English, the tweet reads, “Cocktail ‘Resistance’ While our partners load planes and cars with weapons for Ukraine, we are preparing our branded ‘brotherly’ gift for the Russian bastard. We are arming ourselves, preparing, destroying the occupiers!”

On Friday, Deputy Defense Minister Hanna Maliar also encouraged Ukrainians to make the homemade incendiary devices in a Facebook post, the Washington Post reports. Following that post, in which Maliar wrote that “it is important that everyone resists,” Google searches for “how to make a Molotov cocktail” jumped in Ukraine, the Post reports.

The Ukrainian government is also handing out weapons of its own, with about 18,000 distributed in Kyiv alone thus far, according to the Post, and 70,000 AK-47 rifles distributed on Thursday alone. “When I heard the explosions I decided that I am ready” to fight advancing Russian forces, Olena Sokolan, a civilian who received a rifle, told the New York Times. “I am adult woman, I am healthy and it’s my responsibility.”

A thriving civil society, too, in which solidarity, activism, and charity are encouraged, is part of the war effort, and although the bulk of military assistance is coming from outside sources, those organizations are critical to equipping and supporting the military.

“There are all kinds of charitable foundations and funds. So that kind of ecosystem and infrastructure is there,” Mylovanov said.

The Ukrainian military has received training from NATO members, including the US, and for the past few months has also received weapons like Stinger missiles and Javelin anti-tank weaponry from NATO member states — primarily from US-supported transfers by Latvia, Estonia, and Lithuania.

More weapons and more defense funding have poured in since the start of the invasion on February 24, with even Germany — a holdout both on equipping Ukraine and imposing forceful sanctions to Russia — announcing Saturday that it would send 1,000 anti-tank weapons and 500 Stinger missiles to Ukraine, in addition to authorizing the Netherlands to deliver 400 rocket-propelled grenade launchers.

Also on Saturday, the US announced $350 million in new military aid to Ukraine, including “anti-tank and air defense capabilities.”

In addition to direct aid from Ukraine’s western allies, both Come Back Alive and Phoenix Wings have received crowdfunded donations in the lead-up to the Russian invasion, providing weapons and materiel to those on the frontlines.

Despite the obvious buy-in from the Ukrainian public and a volunteer infrastructure providing strong support to the military, it’s important to keep perspective. Russia’s military is far larger and far more technologically advanced than Ukraine’s, which has fewer than 200,000 active-duty members to Russia’s 900,000. (Not all of which are currently deployed — by some estimates, Russia has about 200,000 troops in and around Ukraine, though numbers vary.) Russia has been building its armed forces for decades, and has far superior air and sea power; Ukraine’s professional army, meanwhile, had to be rebuilt from 2014.

Still, Russia has suffered serious setbacks in the invasion, and has thus far been unable to take Kyiv, Ukraine’s capital, three days after launching an all-out invasion. A majority of the Russian forces that had amassed on the border are currently fighting in the country — about 150,000 troops — but in Kyiv and other cities, Ukrainian forces have been able to hold them off.

As of Saturday, according to Ukraine’s defense ministry, some 3,000 Russian troops had been killed in the fighting, and about 100 Russian tanks destroyed. Those numbers should be treated with caution, as Vox’s Jen Kirby and Jonathan Guyer have pointed out, but would represent a major loss for Russian forces if accurate.

The Russian troops are “increasingly frustrated by their lack of momentum,” one Pentagon official told the New York Times Saturday, stymied by the Ukrainian resistance and other logistical issues.

And with new economic and tactical support from NATO member states — plus the mass mobilization of its people — Ukraine may be able to hold on much longer than Russia could have imagined.