Maoist Rebels in Nepal have overrun a joint army-police base in the western part of the country, reportedly killing more than 100 government troops.

Officials in Kathmandu say Maoists attacked a military base near the village, Gam, in Nepal's far western Rolpa District - about 450 kilometers west of Kathmandu. Forty soldiers and 60 policemen were deployed at the base.

The Maoist attack follows the beginning of a government offensive against a mountain-top Maoist base in another part of Rolpa District. It is the biggest offensive by government troops so far in six year Maoist insurgency. Authorities say they have killed more than 500 Maoists in the operation, but the claim cannot be independently confirmed.

The increased fighting comes as Nepalese Prime Minister Sher Bahadur Deuba is in Washington, for meetings with President Bush and other American officials. The Bush Administration has asked Congress to provide $20 million in non-combat military aid to Nepal, to help fight the insurgency.

A U.S. military assessment team recently completed a visit to Nepal, conducting an in-depth review of the Nepalese military's capabilities.

More than 4,000 people have died in the insurgency. More than half of those casualties occurred in the last six months, after the Maoists walked out of peace talks. Nepal's King Gyanendra then authorized a state of emergency, allowing Nepal's Army to join police in fighting the rebels.

Maoist leaders offered to renew peace talks last week, but the offer was rejected by Prime Minister Deuba, who says the Maoists must surrender their arms before any talks can begin.