Kabul, June 30 (Reuters): Two Taliban suicide bombers today killed at least 27 people and wounded around 40 in an attack on buses carrying newly graduated cadets on the western outskirts of Kabul, officials said.

The attacks underline the threat to security in Afghanistan about a week ahead of a Nato summit in Warsaw.

The green buses, clearly identifiable as police vehicles, were attacked and partially destroyed as they approached the capital from neighbouring Wardak province, leaving debris strewed across the road.

An interior ministry official said at least 27 people were killed and 40 wounded in the attack during Ramazan. In a statement, the Taliban said around 150 police had been killed and dozens injured.

Taliban spokesman Zabihullah Mujahid said the first attack targeted a bus carrying police cadets and instructors. Then, as rescuers and emergency services arrived, a second bomber rammed his car, packed with explosives, into their vehicles, killing dozens.

The attacks were immediately condemned by Nato.