A 10-day-old hostage standoff in this former Soviet republic broke Friday when a rebel warlord and the Tajik government began swapping captives for guerrilla fighters, a Russian news agency said.

Russian Vice Premier Vitaly Ignatenko, who has been talking to rebel warlord Bakhram Sadirov by telephone, told the ITAR-Tass news agency that the exchange had begun at the rebel base in Kalainav, 50 miles east of Dushanbe.Russian new agencies also reported that Sadirov had demanded 300 automatic weapons, four grenade launchers and ammunition as part of the deal, but it was not clear whether this condition was met.

After reportedly killing one U.N. hostage, Sadirov said Friday he would release the remaining 13 captives if his comrades were brought to his base from neighboring Afghanistan.

It was not clear whether the reported execution actually took place. After speaking by phone with one of the hostages, a U.N. observer, Ignatenko said Friday that all 14 hostages were still alive.

Russian journalists among the hostages had reported the death by telephone Thursday, but it was not known whether they were speaking freely or forced to give such an account.

The hostages included eight U.N. workers, four Russian journalists, their driver and Tajikistan's security minister.

"Act like a man. It is not proper to hold women, journalists, and foreigners," Ignatenko told Sadirov earlier Friday, according to ITAR-Tass.

Sadirov allegedly ordered the execution Thursday, angry because he believed the Tajik government had failed to return his comrades from Afghanistan as promised.

The report came from correspondents for the Russian news agencies Interfax and ITAR-Tass and the independent network NTV. They did not identify the U.N. observer or provide many details.

Sadirov reportedly had agreed to free his prisoners after the government pledged to bring home guerrillas led by his warlord brother.

The Sadirov brothers once fought with the opposition in the civil war that has battered this former Soviet republic in Central Asia for years. Their loyalties now are unclear.

In December, Sadirov seized 23 people, including nine U.N. workers. All were released unharmed.