Afghanistan ? Thousands of U.S. Marines and hundreds of Afghan troops poured into Taliban-infested villages of southern Afghanistan with armor and helicopters Thursday in the first major operation under President Barack Obama’s strategy to stabilize the country.

The offensive was launched shortly after 1 a.m. today local time (3:30 p.m. CDT Wednesday) in Helmand province, a Taliban stronghold and the world’s largest opium poppy producing area. The goal is to clear insurgents from the hotly contested region before the nation’s Aug. 20 presidential election.

Officials described the operation, dubbed Khanjar, or “Strike of the Sword,” as the largest and fastest-moving of the war’s new phase and the biggest Marine offensive since the one in Fallujah, Iraq, in 2004. It involves nearly 4,000 newly arrived Marines and 650 Afghan forces. British forces last week led similar, but smaller, missions to clear out insurgents in Helmand and neighboring Kandahar provinces.