Kabul/Madrid - Two NATO-led Spanish soldiers were killed and four were wounded when a suicide bomber attacked their convoy in Afghanistan's western Herat province, Afghan and Spanish officials said Sunday.

The bomber rammed his explosives-laden van into a convoy of Afghan and NATO soldiers in the Shindand district on Sunday morning, Abdul Raouf Ahmadi, spokesman for police forces in western Afghanistan, said.

"According to our information, two NATO soldiers were killed and four others were wounded in a suicide attack that happened in Azizabad area," Ahmadi said, adding that an Afghan passerby was also wounded.

He said that the dead and wounded soldiers were Italian, but Spanish defence ministry in Madrid said that two of their soldiers were killed and another was wounded in Herat on Sunday.

The attack occurred near the Spanish base in Herat, the ministry said, giving no further details.

NATO spokesmen were not immediately available to confirm the incident.

Such attacks are rare in Herat, which along with other western provinces is relatively peaceful compared with southern and eastern regions of the country, where Taliban militants are the most active.

Taliban militants took responsibility for Sunday's attack in a statement posted on their website and said that one of their fighters, Mullah Habibullah, who was resident of the province, carried out the attack.

The statement claimed that an "American military tank was destroyed and several soldiers inside were killed."

Spanish, Italian and Lithuanian soldiers are stationed in western region. There are some 780 Spanish soldiers in the Nato-led International Security Assistance Force from 
40 nations deployed in Afghanistan.

In another incident Sunday, Afghan police and intelligence agents arrested a suspected would-be suicide bomber in Adraskan district of Herat province, Ahmadi said.

"The arrested terrorist is from Pakistan and he had planned to attack Afghan and friendly forces in the province," he said.

Militants from the Taliban, which lost power in late 2001 in a US- led military invasion, have recently increased their attacks on Afghan and the some 70,000 international troops in the country.

Meanwhile, an Afghan army soldier was killed when their vehicle was struck by a roadside bomb blast in Pul-e-Sayed Khail area of south-eastern province of Khost on Saturday, defence ministry said in a statement.

The militants rely heavily on use of suicide and roadside attacks as part of their campaign against the Western-backed Afghan government.

The defence ministry statement also said that Taliban killed two Afghan civilians on charges of working with Afghan government in Yaqoubi and Mandozi districts of the same Khost province.

More than 4,000 people - mostly insurgents - have been killed in the conflict in Afghanistan so far this year. (dpa)