The former Prime Minister of Pakistan was ousted on April 9 after a no-confidence motion. Opposition parties said the vote was called over poor performance in economic and social indicators, poor governance, political victimisation of opponents, and mismanaging the economy and foreign policy.
However, Mr Khan has insisted the motion was part of a foreign-backed conspiracy.
In March, Mr Khan’s government claimed it had a diplomatic cable from March 7, containing a “threat” from the US stating their desire to see Mr Khan’s ousting from office.
Mr Khan claimed Donald Lu, Assistant Secretary of State for the South and Central Asian Affairs, sent the letter, but he denies this.
The US official said the US is closely monitoring the situation in Pakistan and “we respect and support Pakistan’s constitutional process and the rule of law”.
Now, Mr Khan has taken to Twitter following a rally in Karachi on Saturday, thanking supporters and continuing to claim he was ousted in a coup.
He said: “Thank you Karachi for your momentous & passionate support for our jalsa last night.
“This is our fight for democracy & the sovereignty of Pakistan & against a US-initiated regime change conspiracy abetted by local abettors & corrupt political mafia.”
Mr Khan also adopted a conciliatory approach to India and various western nations despite previous tensions between Islamabad and New Delhi.
He said at the rally: “I want to tell the nation that I’ve never been against any country.
“I’m not anti-India, anti-Europe or anti-US. I’m with the humanity of the world. I’m not against any nation.
“I want friendship with everyone but slavery with no one.”
Saturday’s rally in Karachi is believed to have seen at least 30,000 people support Mr Khan.
Two provincial and federal intelligence agencies reported about 30,000-35,000 people attended the PTI’s public gathering.
Meanwhile one federal and two provincial agencies have reported a headcount of more than 60,000 people.
A senior police officer, speaking on the condition of anonymity, told Geo.TV more than 100,000 people attended the jalsa on Saturday, adding that people were seen walking towards the ground when Mr Khan was addressing the crowd.