More than 700 additional US troops arrived in Iraq's increasingly volatile Diyala province on Tuesday, to try to quell burgeoning violence just northeast of Baghdad during a security crackdown there. The Army's 5th Battalion, 20th Infantry Regiment, 2nd Infantry Division moved from northern Baghdad into in Baqouba, Diyala's provincial capital, early Tuesday, to supplement about 3,500 American soldiers already stationed there. Fifteen Stryker armored vehicles pulled into Baqouba from Taji, just north of Baghdad, at 9:30 a.m. after leaving their base under a thunderous outgoing artillery barrage. The move comes at a time when more than 20,000 new American troops are pouring in to Baghdad - the so-called "surge" - as part of a US-Iraqi push to pacify the capital. The idea is to bring Baghdad's violence down to a level that is manageable for Iraqi forces, in hopes that the fragile Iraqi government has room to function.