The popular opposition leader, who was ousted from power in a no-confidence vote last April, was arrested at his home in the eastern city of Lahore on Saturday, soon after a court handed down its verdict.

It is the second time the 70-year-old former cricketer has been arrested this year, having been held on corruption charges in May before Pakistan's supreme court ordered his release days later.

It sparked a wave of deadly protests that saw Khan's followers attack government and military property across the country.

In a video message recorded in anticipation of his latest arrest, Khan urged people to peacefully take to the streets, saying: "You should not sit quietly at home."

But widespread protests are yet to materialise, with supporters fearing the consequences following a crackdown including arrests of members of Khan's Pakistan Tehreek-e-Insaf (PTI) party after the clashes in May.

Khan was held over Saturday night in Attock prison, in the eastern Punjab province, which has armed guards in watchtowers and is notorious for its harsh conditions, with inmates including convicted militants.

Authorities have tightened security around the prison, putting up barriers and blocking roads to keep people away.

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PTI lawyer Shoaib Shaheen said police at the jail had refused entry to a legal team that went to visit Khan.

The politician has denied any wrongdoing and his political party says it will appeal the guilty verdict for unlawfully selling state gifts while he was prime minister between 2018 and 2022.

The sentence could bar him from standing in the country's upcoming elections and critics say the case is politically motivated as authorities fear Khan's popularity and large support base.

Pakistan's information minister Maryam Aurangzeb denied Khan's arrest was linked to the elections and said he had been "proven guilty of illegal practices, corruption, concealing assets and wrongly declaring wealth in tax returns".

Since he was ousted, Khan has been hit with more than 150 legal cases, including allegations of corruption, terrorism, and inciting violence over the protests in May.