A Pakistan court handed Imran Khan a 10-year jail term on Tuesday for leaking state secrets, his party said, the harshest sentence against the former prime minister so far and just 10 days before a general election.

The special court found Khan guilty of making public the contents of a secret cable sent by Pakistan's ambassador in Washington to the government in Islamabad, his Pakistan Tehreek-e-Insaf (PTI) party said. Former foreign minister Shah Mehmood Qureshi was also sentenced to 10 years in the same case.

The jail term is the second conviction for Khan in recent months, and ensures the popular former prime minister will remain in jail, and out of the public spotlight, ahead of next week's general elections. The court was due to issue its written verdict later.

The PTI said it would challenge the decision. "We don't accept this illegal decision," Khan's lawyer Naeem Panjutha posted on social media platform X, formerly Twitter.

Khan aide Zulfikar Bukhari said that the legal team was given no chance to represent the former prime minister or cross examine witnesses, adding that the proceedings were carried out in jail.

He called the conviction an attempt to weaken support for Khan. "People will now make sure they come out and vote in larger numbers," he said.

The embattled former cricket star was previously sentenced to three years in a corruption case, which had already ruled him out of the general elections next week.

However, Khan's legal team was hoping to get him released from jail, where he has been since August last year, but the latest conviction means that is unlikely even as the charges are contested in a higher court.

Khan has been fighting dozens of cases since he was ousted from power in a parliamentary vote of no confidence in 2022. 

Khan says the cable that pertains to the case was proof of a conspiracy by the Pakistani military and the US government to topple his government in 2022 after he visited Moscow just before Russia's invasion of Ukraine.

Washington and the Pakistan military deny the accusations.

The former prime minister has previously said the contents of the cable appeared in the media from other sources.

Khan's PTI, which won the 2018 elections, suffered a major setback earlier this month when a court upheld the Election Commission's decision to strip the party of its traditional election symbol, the cricket bat.

His candidates are now contesting as independents, many of them on the run amidst what the party calls a crackdown backed by the country's powerful military. The military denies this.