Afghan guerrillas have stepped up rocket attacks on Kabul days before the 11th anniversary of the coup that installed a communist government and ushered in a turbulent era that has claimed 1 million lives.

Two explosions echoed over Kabul Monday, sending columns of dust into the cloudy sky, as government troops blasted at Moslem rebel positions in the snowcapped mountains ringing the capital.Mujahideen rebels are using rockets that spray lethal shrapnel over a wide area, killing as many people as possible.

At least 15 people have died and 21 have been wounded in attacks on the city of 2.5 million in the past four days.

On Thursday, one of the usually inaccurate rockets scored a direct hit on the Soviet Embassy, blowing out windows but injuring no one.

The pro-Soviet government of President Najibullah has invited hundreds of foreign guests and journalists to attend the April 27 anniversary of the 1978 military takeover that brought the communists to power.

Kabul's muddy streets have been decorated with red flags and banners to commemorate the day Marxist officers stormed the presidential palace.