Hundreds of US-led troops have launched an offensive against al-Qaida and Taliban militants in eastern Afghanistan, while a bomb attack near the capital killed three German nationals, officials said Wednesday. The offensive involving ground troops and airstrikes in Tora Bora region of eastern Nangarhar province is targeting "hundreds of foreign fighters" who are using dug-in fighting positions, said coalition spokeswoman Capt. Vanessa Bowman. The remote mountainous area bordering Pakistan was heavily bombarded in late 2001 by the US troops hunting Osama bin Laden and his associates following the Sept. 11 attacks in America. Bin Laden is believed to have escaped that assault.