The Russian military on Sunday accused Chechen rebels of detonating bombs containing toxic chlorine and ammonia in Grozny, capital of the breakaway republic.

The rebels had set off several such bombs overnight and early on Sunday near Russian positions in the east, but that the wind had blown the green cloud over the rebel- held city center, the

Itar-Tass news agency reported, quoting the press service of the headquarters of federal forces in the North Caucasus.

Tass said the troops were equipped for chemical attacks and had not been affected, but that the cloud could harm the civilians still trapped in central Grozny.

Meanwhile, federal forces continued massive air strikes on rebel positions in Grozny and in the southern town of Vedeno, the Interfax news agency reported.

Despite bad weather, Su-25 attack planes, Su-24 bombers and Mi-24 combat helicopters have flown about 100 missions against rebel's mountain bases and camps, arms depots, mobile communication stations and strongholds near the villages of Dubai-Yurt, Chishki, Itum-Kale, Kharachoi, Shalazhi, Orekhovo and Maliye Varandy.

Together with border guards, the federal troops continued to block the rebels' possible routes of retreat to territories outside Chechnya, including Georgia, Interfax said.