Italy's center-left opposition dealt a setback to Premier Silvio Berlusconi's coalition Monday by sweeping by-elections for seven seats in the lower house of parliament, including one vacated by Umberto Bossi, a strong ally of the Italian leader. All seven seats in the Chamber of Deputies went to politicians in the center-left Olive Tree coalition, according to results released by the Interior Ministry. Before the vote, the center-left held four of those seats, and Berlusconi's center-right alliance had three. Berlusconi's coalition lost in Milan, the premier's power base and the city where he made his fortune as a TV tycoon. The voting district around Naples _ where the Italian leader went to campaign this weekend _ also swung to the left in a tight vote. --More 0012 Local Time 2112 GMT