Thais voted under tight security Sunday in by-elections that are the first test at the polls for new Prime Minister Abhisit Vejjajiva, who is hoping to strengthen his shaky coalition. Voting closed at 3:00 pm (1300 PST) for 29 parliament seats across the kingdom, with both Abhisit's Democrat Party-led coalition and the opposition hoping to weaken the other side's showing in the 480-member parliament. Official results are expected late Sunday and Monday, but Abhisit said his party had won seven of the seats, and estimated that the Democrat Party's coalition partners won most of the others up for grabs. "The government will gain not less than 20," he told reporters.