Imran Khan was arrested in Islamabad during a court appearance over anti-graft charges. His Pakistan Tehreek-e-Insaf political party has urged supporters to "shut down Pakistan" in protest.
Pakistani former Prime Minister Imran Khan was taken into custody by paramilitary forces on Tuesday.
The former leader was arrested during a court appearance in Islamabad over anti-graft charges.
"Imran Khan has been arrested in the Qadir Trust case," the Islamabad police said on Twitter.
Interior Minister Rana Sanaullah told reporters that Khan was arrested by Pakistan's anti-corruption body, the National Accountability Bureau (NAB), after he did not appear before a tribunal "despite notices."
The NAB had issued arrest warrants for Khan on May 1, accusing him of "corruption and corrupt practices."
In a pre-recorded video released by party officials, Khan said "by the time these words reach you I would have been detained under an illegitimate case."
It appears late Tuesday that Twitter, Facebook and YouTube have been restricted across Pakistan, according to internet monitoring company Netblocks.