MOSCOW, March 31 (Reuters) - An attack on a police commando convoy in Chechnya which killed four Russians and left 39 missing shows rebels have regrouped since losing their last strongholds, the Russian military said on Friday.
"The extremists have managed to restore command and control of their units and have regrouped forces," Interfax news agency said.
The agency quoted Russian officers in the Chechen capital Grozny as saying at least 1,000 fighters had gathered in the mountainous Vedeno and Nozhai-Yurt districts in the south of Chechnya, which is officially under Moscow's control.
On Tuesday the rebels ambushed a convoy of Interior Ministry special police near the town of Zhani-Vedeno in the Vedeno district, southeast of Grozny, killing at least four commandos.
The exact number of casualties remains unknown. Reinforcements have yet to break through.
Sergei Yastrzhembsky -- President-elect Vladimir Putin's Chechnya spokesman -- told Interfax 39 men from the convoy were still missing.
"We will search the area for the commandos until we find them dead or alive," Yastrzhembsky said, although there were reports rebels were still in control there.
The Interior Ministry has many units in Chechnya, including special "OMON" police as well as ground troops. With Defence Ministry forces, there are some 90,000 servicemen in Chechnya.
Last month 20 police commandos were killed when the rebels ambushed another Russian convoy in Grozny. Their deaths were blamed on commanders' carelessness and a lack of coordination. Generals vowed it would never happen again.
Moscow sent additional forces to the site of the latest ambush from other parts of Chechnya and from central Russia. Troops were raining shells and rockets on guerrilla positions there, Interfax said, quoting the military.
War of attrition looms
The rebel build-up seemed to have come as a surprise for Russian generals who had repeatedly said they had broken the backbone of separatist resistance and were chasing small isolated groups of undersupplied rebels through the mountains.
The military has said after the fall of the last major rebel stronghold of Shatoi earlier this month that the large-scale military operation was virtually over and troops would soon start to pull out of Chechnya.
Reports of military victories in Chechnya helped Putin, the mastermind of the campaign, win a straight victory in last Sunday's presidential election.
But mounting losses in what Russia says is the last phase of its more than six-month long war revived memories of the 1994-96 campaign when rebels forced Moscow to withdraw by staging lightning hit-and-run attacks which exhausted the army.
Ruslan Aushev, president of neighbouring Ingushetia, where tens of thousands of Chechen refugees have found shelter, told Interfax on a visit to London there was no other way to stop the war but to start negotiating with the rebels.
"The latest events show that the armed units will go on with guerrilla war tactics, which with the onset of warm weather may turn into a war of attrition against federal forces with new casualties, including civilians," he said.
Human Rights Representatives troop to Chechnya
International human rights groups and aid agencies have already criticised Russia's handling of the war in Chechnya, saying it was affecting thousands of innocent civilians.
Moscow has allowed foreign delegations to visit Chechnya on several occasions and Putin on Thursday gave the go-ahead for the International Committee of the Red Cross to visit several detention centres, including a much-criticised camp in Chechnya.
The United Nations human rights chief, Mary Robinson, arrived in Moscow on Friday for a trip to the region.
Robinson has been an outspoken critic of the Chechnya campaign and was previously denied access to the region.
- Reuters - Thomson Reuters Foundation
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