Kabul  - A suicide bomber rammed his explosive-laden vehicle into a convoy of NATO-led forces in western Afghanistan on Saturday, wounding four soldiers, officials said Saturday.

The bomber attacked Italian troops near an airport on the outskirts of the capital of Herat province, regional police spokesman Abdul Raouf Ahmadi said.

"The bomber died in the attack, and one of the Italian military tanks was thrown out of the main road, because the blast was very powerful," Ahmadi said.

A spokeswoman for NATO-led International Security Assistance Force (ISAF) in Kabul confirmed the attack and said there were troop casualties, but she declined to provide more details.

However, a senior police official in Herat province, who did not want to be named because he was not authorized to talk to media, said four Italian soldiers were wounded in the blast.

No group claimed responsibility for Saturday's attack. Taliban militants who lost power in late 2001 in a US military invasion have carried out hundreds of similar attacks.

Around 2,400 Italian troops are station in Afghanistan, with most of them in western region. The soldiers are part of more than 50,000 ISAF forces deployed in the country from 40 nations following the ouster of the Taliban regime in late 2001.

Western provinces including Herat have been relatively peaceful compared to southern and eastern regions, where the Taliban insurgents are the most active.

In another incident ISAF forces responded to insurgent rocket attacks in Logar province, some 50 kilometres south of Kabul city on Friday, killing three "terrorists," ISAF said in a statement.

The militants fired several rockets on an ISAF base in Puli Alam, the provincial capital on Friday, the statement said, adding, the alliance forces responded with close-air support.

"The pilots were able to identify the militants, who were carrying weapons and a rocket. The pilots engaged and killed three militants," the statement added. (dpa)