Taliban fighters shot down a US helicopter last week, killing 38 people [AFP]

A roadside bomb has killed five foreign troops in volatile southern Afghanistan, NATO said in a statement.

Thursday's casualties come days after the coalition suffered its worst single loss in the 10-year war when Taliban fighters shot down a helicopter carrying US special forces.

"Five International Security Assistance Force service members died following an improvised explosive device attack in southern Afghanistan today," the US-led coalition said in statement, without giving any further details in line with policy.

Violence is at its worst in Afghanistan since US-backed Afghan forces toppled the Taliban government in late 2001, with high levels of foreign troop deaths and record civilian casualties during the first six months of 2011.

At least 50 foreign troops have been killed so far in August.

Taliban denial

The Taliban insisted Thursday that the fighters who shot down a US helicopter in Wardak province, killing 38 coalition and Afghan forces, were still alive, despite a US announcement that they had been killed.

"This is not true. After seeing the enemy statement, we contacted the mujahed [fighter] who shot down the helicopter and he's not dead. He's busy conducting jihad elsewhere in the country," Taliban spokesman Zabiullah Mujahid told AFP.

Mujahid was responding to NATO claims that it had killed those Taliban in an airstrike.

"The [Wednesday] strike killed Taliban leader Mullah Mohibullah and the insurgent who fired the shot associated with the August 6 downing of the CH-47 helicopter, which resulted in the deaths of 38 Afghan and coalition service members," NATO had said in a statement on Wednesday.

The statement did not say explicitly that the Taliban fighters had shot the helicopter down, although it was the clearest indication yet from NATO sources that it was the likely cause.

Source: Agencies