Nine Russian soldiers died and three were injured near Chechnya's capital when a militant-fired grenade brought down a building in which they were sheltering, officials said on Tuesday. "The militants attacked our base in the old factory, when a grenade knocked the wall down," said one officer as he stood next to the ruins of the disused building on the edge of Grozny. Troops had moved into the factory on Monday to spend the night there when they came under fire. Two rebels were killed before rebel fire toppled a support wall in the building. The attack showed that at least some of the militants, who have fought Moscow's rule for a decade, were not abiding by a ceasefire declared by their leaders. The unilateral truce, which was intended to lead to peace talks but has been rejected by Russian officials, is due to end at midnight on Tuesday. According to human rights groups, some 20,000 soldiers have died in Chechnya since Russia sent in troops to crush separatist militants in 1994. Hundreds of thousands of civilians are believed to have been killed.