By Mirwais Harooni
KABUL (Reuters) - Weeping Afghans gathered under tight security on Friday to bury former president Burhanuddin Rabbani, the government's chief peace negotiator, who was killed this week by a suicide bomber posing as a Taliban envoy with a message about possible talks.
After prayers at the presidential palace, a coffin draped in the black, red and green national flag was carried to a hilltop in the Wazir Akbar Khan district for burial.
Crowds along the procession route pushed, shoved and clambered their way through the throngs of mourners to touch Rabbani's coffin as it made its way toward the burial site.
Others chanted "God is great" as the coffin passed by. Hundreds more were clustered on the hilltop around his grave.
Bursts of automatic gunfire briefly unsettled the capital as police fired shots into the air to disperse large groups who moved toward the burial site without having passed tight security checks.
Streets surrounding the capital's political and diplomatic heart were blocked-off and almost empty, with police, soldiers and special forces guarding the funeral procession route.
Rabbani was killed by a man who claimed to be a Taliban envoy with a message of peace from the insurgent leadership.
His death has reignited long-simmering ethnic tensions, stirring fears of retribution. But his supporters called for a peaceful burial on Friday.
"We will avenge the death of our leader but today, please be calm," said a man using a loudspeaker.
MOST DIFFICULT TIME
Car windscreens and walls along normally congested roads were covered with posters bearing the face of Rabbani, an ethnic Tajik and former mujahideen resistance fighter who became president after the fall of the Soviet-backed regime.
"Professor Rabbani's martyrdom is a big loss for Afghanistan and it is a sad day for all of us," said restaurant owner Mohammad Zia.
One of Zia's customers sat sipping tea beneath a window bearing Rabbani's photo and added: "Rabbani was killed at the most difficult time for Afghans, when security is at it's worst and people feel hopelessness."
Condolences and tributes poured in from prominent Afghans and foreign governments condemning Tuesday's killing and urging Afghans not to give up on Rabbani's fledgling peace process.
President Hamid Karzai, who chose Rabbani to head the High Peace Council last October, cut short his trip to the United Nations General Assembly in New York to return for the funeral.
He has come under intense criticism from political opponents who say he instructed Rabbani to meet with the assassin.
Karzai's office has said he was not involved.
(Additional reporting by Hamid Shalizi Writing by Martin Petty Editing by Emma Graham-Harrison and Ed Lane)