By Paul Tait
KABUL (Reuters) - Roadside bombs killed four U.S. soldiers in southern Afghanistan, the U.S. military said on Sunday, the latest deaths in an escalation of violence that has put pressure on coalition leaders over their war strategy.
Thousands of U.S. Marines and hundreds of British soldiers 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 assault by U.S. Marines, Operation Strike of the Sword, is the first major operation under U.S. President Barack Obama's new regional strategy to defeat the Taliban and stabilise Afghanistan, which holds a presidential election on August 20.
It was launched with insurgency violence at its highest since the Taliban's austere Islamist government was ousted in 2001 by U.S. and Afghan forces for failing to hand over al Qaeda leaders wanted over the September 11 attacks on the United States.
Violence has again flared across Afghanistan since the operation began on July 2, with attacks in traditional Taliban strongholds in the south and east as well as in relatively more peaceful areas in the north and west.
The Taliban backlash has put pressure on leaders in Washington and London, who say U.S. and other NATO-led troops have pushed back Taliban insurgents but that a lot of tough fighting remains to be done during the summer.
U.S. President Barack Obama told Sky News on Saturday that the United States and its allies would have to evaluate Afghanistan again after next month's presidential election to see what other military or development steps might be needed.
FIFTH SOLDIER DIES
The latest four soldiers to be killed by roadside bombs, which the U.S. military calls improvised explosive devices, or IEDs, died in two separate attacks in the south on Saturday, a U.S. military spokeswoman said.
"The four killed in two IED attacks in Helmand were U.S. service members," said spokeswoman Lieutenant Commander Christine Sidenstricker. Roadside bombs are one of the most common weapons used by insurgents to attack Afghan and foreign security forces. The Taliban claimed responsibility.
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 released on Sunday. No other details were available.
Washington is pouring in extra troops under Obama's new strategy, with numbers set to more than double to 68,000 by the end of the year. About 90,000 U.S. and NATO troops are already serving in Afghanistan.
British troops mounting their biggest operation of the campaign in Afghanistan have also suffered under the Taliban backlash, with 15 confirmed killed in a 10-day period, including five in two roadside bomb blasts on Friday.
Taliban casualty figures were not immediately available.
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, putting the Afghan campaign sharply into focus at home.
British Prime Minister Gordon Brown telephoned Afghan President Hamid Karzai on Sunday, the presidential palace said in a statement, and Karzai expressed his sympathy over the British casualties.
Brown told Karzai Britain would continue to help the Afghan people in the fight against terrorism and in building up Afghan security forces, the palace said. U.S. commanders have complained of a lack of Afghan troops in the latest operations.
One of the main goals of the new operation is to capture ground from the Taliban and hold it, something overstretched British-led NATO troops have so far been unable to achieve. It is also seeking to win over Afghans from the insurgency.
With the latest deaths dominating headlines, finance minister Alistair Darling said on Saturday British troops would get whatever equipment they needed despite a ballooning deficit putting pressure on the defence budget.
The media, military experts and opposition politicians have questioned the government's strategy and its commitment to equipping troops properly. Britain has sent 700 extra troops for the presidential election period, taking its force to 9,000.
In Helmand, the main British military hospital on Friday coped with the biggest load of battlefield casualties suffered in a day since the Falklands campaign in the 1980s.
But politicians and military leaders have warned often in recent weeks that a bloody summer of fighting lay ahead.
(Additional reporting by Jonathon Burch in KABUL and Peter Graff in HELMAND; Editing by Peter Millership)