NAZRAN, Russia, Feb 13 (AFP) - Russian forces bombarded the Argun gorge Sunday, dropping huge bombs, the Defense Ministry said, as they tried to destroy the last Chechen strongholds in the mountainous south.
The mujahideen, meanwhile, threatened to block Russian tank movements around Grozny, the destroyed capital.
Russian planes intensified their bombardment of Muslim positions in the gorge and were dropping bombs weighing up to 1,500 kg (3,300 pounds), the Defense Ministry announced in Moscow.
Russian forces were surrounding several villages in the gorge, the Interfax news agency reported.
The Russians are mounting a pincer movement against the 7,000 to 8,000 Chechen mujahideen who retreated into the mountain strongholds after the fall of Grozny on February 6, putting the squeeze on the Chatoy region, which the Chechens still hold.
Moscow is said to have poured 50,000 men into the battle for the mountains.
In Moscow the human rights pressure group Memorial condemned the "inhuman treatment" which former prisoners and witnesses claim Russian troops are meting out to detainees in their "filtration camps."
Citing prisoners and a letter apparently from a Russian soldier disgusted by his comrades' actions, the group alleged that detainees are regularly beaten until their limbs break, and are raped and tortured.
Russian Su-24 and Su-25 warplanes and Mi-24 helicopter gunships carried out 100 missions in 24 hours to bomb the Argun and Vedeno gorges, two main access routes to the mountainous area, Russian military headquarters in Chechnya told Interfax.
The Russian warplanes destroyed 18 Chechen bases, two communications stations and two anti-aircraft systems, Interfax said.
Russian forces claimed that the Vedeno gorge, where Russian helicopters dropped paratroopers and long-range anti-tank weapons on Saturday, was under control, Interfax said.
The Defense Ministry said an elite battalion of professional soldiers, all volunteers, would be sent to the region for the "final phase of the operation."
This unit has been training specially for the task in the Russian Ivanono region, the statement said.
Some 1,000 Muslims still located in Grozny are under orders to block routes leading to the city to stop Russian tanks and other vehicles, a spokesman for Chechen President Aslan Maskhadov said.
The Chechens claim to have more than three times the number of fighters in Grozny than Russian figures show. Russian military officials said on Wednesday there were some 300 fighters in the capital.
Grozny had been relatively quiet last week with civilians emerging from the ruins for the first time in weeks .
But overnight Saturday to Sunday, a group of Muslim fighters attempted to break into an area adjacent to the Russian headquarters in Grozny, the Interfax news agency said.
Six Chechens exchanged fire with Russian tanks and troops. No one was wounded in the attack, Russia's private NTV television said.
The Chechen spokesman said the 1,000 fighters in Grozny were able to gain access to and move about the capital by using underground tunnels and the sewer system.
Among the group were some 300 mujahideen who have vowed on the Quran not to leave Grozny alive, the spokesman said.
Russia has tried to block movements in and out of Grozny, but Chechen fighters said that they bribe Russian troops, who are often drunk out of their minds, to allow them to move through enemy lines surrounding the capital.
Russian military headquarters told NTV that Chechen fighters were planning attacks against some 93,000 Russian troops in the Muslim republic and against occupied villages.
Maskhadov on Friday said the Chechens would fight a "regular war," ruling out "terrorist attacks," but stressing that the fighters would never lay down their arms.
Russian forces killed 50 Chechen fighters in a 24-hour period according to preliminary reports, NTV television quoted Russian military headquarters as saying on Sunday.
Maskhadov's spokesman did not provide information on the number of Chechen fighters killed.
