Former Pakistan Prime Minister Imran Khan has been arrested outside the High Court in the capital Islamabad.

Mr Khan was appearing in court on charges of corruption, which he says are politically motivated.

Footage showed paramilitary forces in armoured personnel carriers detaining Mr Khan after he entered the court compound, before driving him away.

He was ousted as PM in April last year and has been campaigning for early elections since then.

General elections are due to be held later this year.

A statement from the inspector-general of Punjab police said the arrest of Mr Khan had been ordered as he was accused of "corruption and corrupt practices".

The case involves allegations over the allotment of land in the so-called Al-Qadir Trust, which is owned by Mr Khan and his wife, Dawn newspaper reported.

Mr Khan denies breaking any law.

In a video message filmed as he travelled to Islamabad - and released by his Pakistan Tehreek-e-Insaf (PTI) party before his arrest - Mr Khan said he was ready for what lay ahead.

"Come to me with warrants, my lawyers will be there," he said. "If you want to send me to jail, I am prepared for it."

The PTI has called on its supporters to come onto the streets - protests have been reported from Lahore and Peshawar. In central Islamabad security was tight for the former PM's court appearance.