Sri Lankan air force planes pounded a Tamil separatists' arms storage and command center deep in the northern jungles Thursday, the military said. The air attacks were part of the government's offensive to crush the Tamil Tigers and seize their de facto state in the north. The government has stepped up fighting around the rebels' defacto state in the north in recent months in an effort to deliver on its promise to crush the group by the end of this year.In the latest assault, air force jets pounded the arms storage in the rebel stronghold of Mullaitivu Thursday morning, said military spokesman. An hour later jets also bombed a rebels' command center near the front lines in the Jaffna peninsula, he said. He said details of casualties and damage were not available immediately.