The comments by King Abdullah, centre, came three days after a man was killed in clashes in Amman [Reuters]

Jordan's King Abdullah II has called for national unity three days after clashes between protesters and government supporters led to the death of one man and left 160 people injured.

"The most important thing now is our national unity, which must not be touched," the king told tribal leaders on Sunday in the southern town of Petra, a major archaeological and tourist site.

"We need to stay away from any behaviour or attitude that would affect our unity."

Jordan "is going ahead with political and economic reforms, strongly and enthusiastically. There is nothing that we fear," the state-run Petra news agency quoted the king as saying.

"We understand the difficult circumstances and challenges in the country and the region, but we are optimistic about the future that we are trying to build."

Cheering subjects waved Jordanian flags and chanted "long live our beloved king" as Abdullah stood outside his vehicle to salute them.

'Fatal beating'

The king's comments came as Jordanians mourned the death of 55-year-old Khairi Saad who died in the unrest that has been rocking the country for the past three months and much of the Arab world.

The man was killed as police broke up a pro-reform protest camp set up near the interior ministry in the capital, Amman, after 200 government supporters threw stones at 2,000 young demonstrators.

Saad's family has said he died after "receiving several blows to his body," but the coroner said a post-mortem proved he died of heart failure.

"The cause of the death was heart failure," Qais Qsous, the chief forensic doctor, said. He insisted that there were "no marks of beatings on his face and body".

The government claimed Saad as a supporter, while the opposition and his brother, Saeed Saad, disputed that, saying his brother was "brutally beaten" by police.

"He was a follower of the Muslim Brotherhood," Saeed said. The Brotherhood's political arm, the Islamic Action Front, is Jordan's largest opposition group.

He said his brother joined anti-government protesters on Thursday and camped out in an Amman square with the crowd. The clashes with government supporters erupted on Friday.

"He was bringing food to the group when police beat him to death," he said.

"I saw blood on his face when we took him to the morgue for an autopsy," he said. "There were clear marks of torture and beatings on his face."

It was the first death since the outbreak of pro-reform protests in Jordan three months ago.

The Islamist opposition and other groups, which called on Saturday for the ouster of Marruf Bakhit, the prime minister, have been urging sweeping political reforms, including an amended electoral law, leading to a parliamentary government and elected premier.

Parliament on Sunday rejected calls to limit the king's powers to pave the way for a constitutional monarchy.