The United Nations has suspended humanitarian operations in the breakaway Russian republic of Chechnya after the kidnapping of a Russian aid worker, officials said.

Humanitarian programmes are also to be halted for two days in neighbouring Ingushetia - home to about 150,000 Chechen refugees.

This was a difficult decision to make but the safety of our workers is our top concern

UN spokeswoman Viktoria Zotikova

This follows the abduction last week of Nina Davidovich, the head of a Russian group working with the UN children's fund (Unicef).

An expert on Chechnya, author Tom de Waal, says the suspension is "extremely serious. It will affect between half a million and one million people, some quite directly."

Chechnya was swept by a wave of abductions of humanitarian workers, journalists and others after the first war of independence with Moscow in 1994-96, mostly motivated by ransom.

Mr de Waal estimates that there are at present several dozen local people being held by kidnappers.

Last year, the UN and other agencies suspended operations there after the kidnapping of an American relief worker.

Kenny Gluck, who worked with Medecins Sans Frontieres was released unharmed in February 2001 after nearly four weeks in captivity.

Mission to Chechnya

According to Russian media reports, Ms Davidovich was kidnapped in Chechnya last Tuesday after unidentified gunmen stopped her car and fired shots.

It remains unclear who was responsible, and no ransom demand has yet been made, according to the UN.

Grozny has been devastated by war

Senior UN representatives have left for Chechnya to discuss the abduction and the situation in the region with Russian officials.

UN relief agencies have been providing food aid to tens of thousands of people in Chechnya and also help run education and health care programmes.

The aid operations are being halted indefinitely, apart from a water distribution project in the capital Grozny which is viewed as indispensable.

The decision to suspend relief programmes was difficult to make "since it will affect the population of Chechnya... But we made such a decision because the safety of our workers is our top concern," a UN spokeswoman told the Associated Press news agency.

The programmes are likely be resumed if Nina Davidovich - the head of non-governmental organisation Druzhba (Friendship) - is released, said Viktoria Zotikova, at the UN office for humanitarian affairs in Moscow.

Meanwhile, Russian helicopter gunships continued strafing mountains in the south of Chechnya on Monday. They were aiming to kill a group of rebels Russia said Georgian border guards had failed to turn back.

Moscow used the occasion to reiterate its demand that Russian troops be allowed into Georgia.

Reducing abductions

The spate of kidnappings was given by Russian officials as one of the reasons for troops were sent back into Chechnya in the autumn 1999.

Victims included four employees of a British telecommunications company who were subsequently beheaded.

Correspondents say the Russian military presence in Chechnya has helped reduce the number of abductions, but has not ended them.