A week of fierce fighting between anti-communist insurgents and Afghan government forces holding a strategic city has killed scores of people and wounded hundreds, a guerrilla spokesman said Saturday.

Thousands of guerrillas blasted Jalalabad in a relentless attack with long-range rockets and heavy artillery, said Mohammad Shoaib of the Jamiat-e-Islami insurgent group.The city, Afghanistan's fifth-largest, is seen by the guerrillas as a stepping stone to the capital of Kabul, 75 miles to the west.

"Fighting is close to and around the city," said Shoaib. "There are rumors that some mujahedeen (guerrillas) have entered the city from the north, but there is no confirmation."

Several guerrilla sources said the insurgents now control a key government garrison on the outskirts of Jalalabad, which is 45 miles west of the border with Pakistan where many guerrilla groups are based.

The guerrillas captured as many as 500 government troops in the battle for the post, said Naeem Majrooh of the Afghan Information Center, which opposes the Marxist government.

Majrooh said casualty figures "are very high. Most of the deaths are from mines and bombardments."

The government of Afghan President Najib said 1,500 guerrillas had been killed in the weeklong fighting around Jalalabad. It did not give figures for government forces.

The official Soviet news agency Tass said Afghan government forces in Jalalabad attacked the rebels with bomb strikes and rockets, killing 350 insurgents and wounding 200. It said government units suffered 15 killed and 12 wounded.

Tass also said a large government convoy reached Jalalabad from Kabul with arms, ammunition and reinforcements.

Western journalists returning from the Afghan-Pakistani border said a convoy of ambulances was headed for Pakistan.

The International Committee of the Red Cross runs a hospital in Peshawar, Pakistan, about 30 miles from the border, and the staff reportedly was working around the clock treating war wounded.

Afghanistan's official Radio Kabul, monitored in Islamabad, said nine rockets hit the capital Saturday, killing one person and injuring another.

The Tass dispatch said a Soviet civilian jet of the Aeroflot airline was slightly damaged in a rocket attack on Kabul airport.

It did not say if the plane was on the ground or in the air or if there were any casualties, but it said the rockets killed an unspecified number of people in residential buildings mear the airport.

Najib asked the United States and the Soviet Union to intervene to stop the fighting, according to a radio report Friday.

The guerrillas have been fighting the government since a Marxist coup in 1978 and have vowed to overthrow Najib now that the Soviets are gone.

They recently formed an interim government and on Friday held their first Cabinet meeting inside Afghanistan, about seven miles from the border in eastern Paktia province.