In Nepal, fresh violence has erupted in the capital, Kathmandu, on the fourth day of a blockade imposed by Maoist rebels. The rebels are not backing down, even though the government has agreed to one of their key demands. Officials in Nepal say two men on a motorcycle shot and killed a police officer on the outskirts of Kathmandu. They are blaming the attack on Maoist rebels. This is the second day that violence has hit the city and the fourth day of a Maoist blockade of the capital.

The rebels have not erected physical barriers around the city, but have threatened attacks on those trying to enter or leave.

The rebels have vowed to keep the city cut off, until the government releases jailed Maoists and provides information on detained colleagues.

The government did offer on Friday to investigate the fate of rebels Maoists say have gone missing after being detained. That offer came hours after several bombings in Kathmandu. The besieged city is facing shortages, but experienced some relief after the Maoists did allow a dozen trucks loaded with fresh food to enter Kathmandu. The city does not have any rail links, and food, fuel and other supplies are trucked in.

Several buses carrying tourists also left the city under armed escort. Hundreds of tourists and travelers have been stranded by the blockade. Rajendra Dahal, editor of the Himal news magazine, says the rebels have succeeded in showing their power extends beyond their rural bases.

"They just wanted to show their presence, to create some type of pressure, some type of terror within Kathmandu valley," he said. Local reports say the Maoists are threatening to widen the blockade to neighboring districts of Kathmandu that border Tibet. The government has offered to restart peace talks to end the eight-year insurgency, but the rebels will only do so, if strict preconditions are met.

The Maoists want to turn Nepal into a communist republic. Their campaign has claimed more than 9000 lives.

The violence has surged since peace talks broke down last year.