US Secretary of State Hillary Rodham Clinton apologized for the civilian casualties caused by US airstrikes in Afghanistan after a meeting with the leaders of Afghanistan and Pakistan on Wednesday, according to dpa. "We deeply, deeply regret that loss," Clinton said, promising a joint investigation after an airstrike in western Afghanistan this week that may have killed more than 100 people, according to an Afghan regional legislator. Clinton said bringing peace to the region required an "all government effort" that went well beyond military support, amid an uptick in fighting against the Taliban in both Afghanistan and Pakistan. Afghan President Hamid Karzai and Pakistani President Asif Ali Zardari both promised to work together to defeat the "common threat" in their countries, while their foreign ministers agreed to start talks on a transit deal to be completed by the end of the year. President Barack Obama, who will meet with the two leaders later Wednesday, has ordered an extra 17,000 US troops to Afghanistan to confront the Taliban and al-Qaeda, as well as increased non-military support.