Taliban guerillas attacked a convoy of provincial officials and police in the southern province of Helmand, killing three policemen and wounding six, government officials said on Tuesday. In a separate incident, four Afghan aid workers were killed by a roadside blast west of Kabul, police said. The attacks come after several days of some of the heaviest Taliban attacks since they were ousted in 2001 and just as NATO is bringing thousands of extra troops into the country. Full Story