KABUL (AFP) - A string of bombs ripped through parts of Afghanistan on Sunday, killing four US soldiers and three Afghan civilians, officials said, in attacks linked to a Taliban-led insurgency. The Taliban claimed responsibility for the blast that killed the four International Security Assistance Force troopers in the eastern province of Nangarhar, on the border with Pakistan. "It was an IED (improvised-explosive device). Four soldiers were killed," an ISAF spokesman at the force's Kabul headquarters told AFP.A statement said that two were killed immediately and two died later from their wounds. The US military said the four were from the US, which has about 38,000 soldiers in war-plagued Afghanistan. An Afghan media officer in the province said the bomb had been remotely detonated to hit a convoy in Bati Kot district. "These dedicated professionals have risked their lives for a safe and stable Afghanistan," ISAF spokesman Brigadier General Richard Blanchette said. Three other ISAF soldiers died in Afghanistan on Saturday. One was French, another British and the nationality of the third has not been released. Also Sunday, a suicide bomber blew up an explosives-laden vehicle in the capital Kabul as a foreign military convoy passed, the Interior Ministry said, leaving two civilians dead and 14 wounded, although the foreign troops were unharmed. Earlier, a bomb exploded in Kandahar as the mayor, Ghulam Haidar Hameedi, drove past, police said. "One civilian was killed and six others were wounded but there was no harm to the mayor except his vehicle was damaged a bit," police said. The US military said meanwhile that soldiers killed five Taliban in an operation early Sunday about 60km west of Kandahar city. Three others were detained, it said in a statement. Abdul Qayoum Karzai, a brother of President Hamid Karzai, who leads reconciliation efforts on behalf of Kabul, said US President Barack Obama's comments about exploring talks had sparked optimism, including amongst Taliban. "No other way is left but talks," Karzai added. He would not give details about the process citing its sensitivity.