Bombs kill 4 U.S. soldiers in south Afghanistan

KABUL (Reuters) - Four U.S. soldiers were killed by roadside bombs in southern Afghanistan on Saturday, the U.S. military said on Sunday, the latest casualties in an escalation of insurgent violence.

A fifth soldier serving with NATO-led forces in the south died on Friday from wounds received in June, the alliance said in a statement.

Thousands of U.S. Marines and hundreds of British troops have been fighting major new offensives in the past 10 days in Helmand province, a Taliban stronghold and Afghanistan's biggest producer of the opium that funds the insurgency.

"The four killed in two IED attacks were U.S. service members," said U.S. military spokeswoman Lieutenant Commander Christine Sidenstricker, referring to improvised explosive devices, or roadside bombs, one of the most common weapons used by insurgents to attack Afghan and foreign security forces.

The loss of the four Americans was one of the biggest casualty tolls since the Marines launched their assault, Operation Strike of the Sword, on July 2. The British military earlier launched their own offensive in the area.

Seven U.S. soldiers died in attacks across Afghanistan last Monday, including four in a single bombing in northern Kunduz.

British troops mounting their biggest operation of the campaign in Afghanistan have also had casualties at the hands of the Taliban, with 15 killed in a 10-day period, including five in two separate roadside bomb blasts on Friday.

Britain has now lost 184 soldiers in Afghanistan since it joined the U.S.-led war, more than the 179 killed in Iraq since 2003.

(Editing by Tim Pearce)