Gunbattles and a suicide bombing killed 12 gunmen and six policemen across southern Afghanistan on Monday. Insurgents also brought their fight to the capital, targeting NATO patrols with bicycle-rigged bombs that wounded four alliance soldiers. The incessant bloodshed comes amid Afghanistan's deadliest surge in violence since US-led forces toppled the Taliban regime in late 2001 for harboring Osama bin Laden and deployed tens of thousands of soldiers to this war-wracked country. Southern and eastern provinces have witnessed most of the ambushes, suicide bombings and military operations since early this year. But Monday's bombing in the capital, which is patrolled by thousands of NATO-led troops, might signal a new phase in insurgent plans to attack targets in Kabul, which has so far been largely spared from violence.