KABUL, April 13 (Reuters) - Two NATO soldiers have been killed in separate roadside bomb blasts in eastern Afghanistan, bringing the number of foreign troop casualties this week to 11 -- one of the bloodiest weeks for Western forces in months. Two NATO convoys about 8 km (5 miles) apart on separate operations supporting Afghan security forces were attacked within 30 minutes of each other on Thursday, the alliance said in a statement. One soldier was also wounded. As part of a new NATO policy the alliance refuses to detail where attacks occur, saying that could identify the nationalities of the dead before families have been notified. Violence has been rising through the spring following the annual winter lull after last year saw the bloodiest fighting since the Taliban's ouster 2001. Eight Canadian soldiers from the NATO-led International Security Assistance Forces (ISAF) and one from the separate U.S.-led coalition died in bombings in the south this week. It has been the bloodiest single week for the U.S. and NATO -- currently also under U.S. command -- for several months.