A middle-aged woman became the latest civilian casualty in the escalating conflict between Nepal's Maoist insurgents and security forces, less than a week after a mine planted by the rebels blasted a bus and killed 42 passengers.

Maheshwori Bista, in her 40s, was in her sweet shop in Chauraha Bazar, a market square in Dhangadhi district in western Nepal, near the Indian border, when a stray bullet hit her as the communist guerrillas attacked a police post in the area Thursday evening.

The attack came even as international condemnation poured in against the Maoist attack on the bus in southern Chitwan district Monday that killed 42 people, including seven children, and the rebel leadership said they would ensure that civilian casualties did not recur.

Bista, caught in the crossfire, was killed on the spot while an assistant sub-inspector of police was reported to have sustained serious injuries.

The Maoists also simultaneously attacked security personnel guarding important buildings in the area including the offices of the state-run Nepal Electricity Authority and Nepal Oil Corporation, a security barracks and the Dipendra Police School, media reports said.