Sniper teams attacked US Marines and Afghan troops across the Taliban haven of Marjah, as several gun battles erupted Monday on the third day of a major offensive to seize the extremists' southern heartland. Multiple firefights in different locations taxed the ability of coalition forces to provide enough air support as NATO forces forged deeper into the town, moving through suspected insurgent neighborhoods, the US Marines said. In northern Marjah, an armored column came under fire from at least three separate sniper teams, slowing its progress. One of the teams came within 155 feet and started firing. Troops braced for the estimated four-kilometer march to link up with US and Afghan troops who had been airdropped into the town. Small squads of Taliban snipers initiated firefights throughout the day in an attempt to draw coalition forces into a larger ambush. On Monday, Afghan military officials gave a more optimistic view of the progress being made, with Brig. Gen. Sher Mohammad Zazai saying Afghan and NATO forces have largely contained the insurgents and succeeded in gaining trust from residents. However, the mission faced a setback on Sunday when two US rockets slammed into a home outside Marjah, killing 12 civilians.