Lawyers representing ousted Pakistani prime minister Nawaz Sharif say they want the country's military ruler, General Pervez Musharraf, to appear as a defence witness.

They were speaking after Mr Sharif was formally charged with attempted murder, kidnapping and hijacking.

The move - long delayed by legal wrangling - comes more than three months after Mr Sharif was overthrown in a military coup.

The authorities say Mr Sharif and others attempted to murder the current military ruler, Pervez Musharraf, and nearly 200 others, when their plane was prevented from landing at Karachi airport on the night of the coup - 12 October last year.

The Pakistan International Airlines plane finally landed with barely seven minutes of fuel remaining after the army took over.

Mr Sharif, his brother, Shabaz, and the five other co-accused, pleaded not guilty at the Karachi court room.

By framing the charges, Judge Rehmet Hussein Jaffri indicated that he believes there is a prima facie case to answer.

He said the men "committed the crime of hijacking and thus endangering the lives of 198 passengers and crew members, including General Musharraf and thus committed an attempt to murder and also unlawfully placing them in confinement."

Hijacking, terrorism and kidnapping all carry the death penalty or life in prison.

However, the judge did not list all the charges requested by the prosecution. He threw out an allegation that Mr Sharif and his co-accused had waged war on Pakistan.

Denial

The ousted prime minister told the court that General Musharraf - and not he - had been responsible for hijacking the plane to try to justify the coup. He said the general had also hijacked democratic rule.

"He unlawfully put a prime minister under detention. I was detained without being charged or without a trial," Mr Sharif said.

"We believe the prosecution has a weak case. We are confident and we don't think the charges will stand up," a member of Mr Sharif's defence team, Khwaja Sultan, said.

The BBC's Owen Bennett-Jones in Karachi says that since the case hinges on the events surrounding the coup, it has a bearing on the legitimacy of General Musharraf's government.

The former chief of Pakistan's Civil Aviation Authority, Aminuddin Chaudhry, was given immunity when he agreed to testify against his fellow accused.

Delays

Security was heavy around the courtroom. Mr Sharif arrived in an armoured personnel carrier, surrounded by vehicles packed with heavily-armed police.

The trial - which the military government has promised will be open and fair - will begin formally on 26 January.

The case had been held up for several weeks, mainly by technical legal arguments about jurisdiction and the nature of the evidence the prosecution should be allowed to use.

A new judge was put in charge last week after proceedings were interrupted because of the presence of plain clothes intelligence officials in the courtroom.