According to Interfax news agency, Usman Imayev told an angry crowd he would not return to the negotiating table until those responsible for killing a family of seven at a farm on the northern outskirts of the city were arrested.
Russian negotiators did not immediately comment but Interfax quoted an unnamed senior military official as saying the killings were a "classic provocation". It would not have been difficult for "extremists" loyal to the Chechen leader, General Dzhokhar Dudayev, to have obtained Russian uniforms and carried out the murders in order to derail the peace talks, he said.
Whatever the truth, chances are now very poor for a quick end to the six-month war, which has killed thousands of civilians and reduced much of Chechnya to ruins.
Most of the dead were victims of the Russian military machine which bore down on the tiny Caucasian region last December with the aim of crushing its independence drive.
Eyewitnesses said the seven Chechens were stabbed to death on Thursday night by a gang of men wearing Russian uniforms who descended on the farmhouse in the settlement of Trety Sovkhoz in an armoured personnel carrier.
Yesterday villagers fought with police to bring the bodies to the headquarters of the Organisation for Security and Co-operation in Europe (OSCE), where the peace talks were being conducted. Finally they broke through the cordon and began a protest demonstration, which Mr Imayev joined. As well as the child, an 80-year-old man was reported to be among the victims.
Last night there were reports that two people were wounded when security forces opened fire on the demonstrators. Negotiators issued a statement announcing a joint investigation into the incident and saying the talks would continue. But it did not say when.
The talks were not going well even before the killings ruined the atmosphere. At the beginning of the week, Russia's negotiator, Arkady Volsky, had the first face-to-face meeting with General Dudayev and extracted from him a promise that he would step down if Chechnya was allowed its sovereignty. But then, either as a result of bungling or deliberate sabotage by hardliners in Moscow, President Boris Yeltsin signed an untimely decree allowing for the permanent stationing of Russian troops in the region.
For their part, the Chechens had undermined Russian confidence by breaking the ceasefire and allowing the guerrilla leader Shamil Basayev to threaten more terrorist attacks on Russian towns.
Mr Basayev's talk of using stolen uranium and biological weapons was dismissed as blackmailing bravado by Russian officials. But he did lead the raid on the southern Russian town of Budennovsk last month when he and his men held about 1,000 hostages in the local hospital before escaping back to Chechnya.
About 100 people died in the raid but it could have been worse had the Russian Prime Minister, Viktor Chernomyrdin, not overruled Kremlin hawks who wanted to use force and negotiated an end to the drama. This success gave Mr Chernomyrdin, an advocate of a political settlement in Chechnya, the authority to start the first serious peace talks in Grozny. But this week Mr Chernomyrdin has been hedging his bets, saying that if the Chechens do not use the opportunity of the talks, they will not get another chance.Reuse content