A car bomb placed by Tamil extremists outside a hotel in Sri Lanka exploded and killed at least 34 people Thursday, military officials said. In retaliation, angry Sinhalese stabbed eight Tamils to death, residents said. The explosion in the port of Trincomalee, 145 miles northeast of Colombo, occurred as more than 100 Sinhalese in a marketplace adjacent to the hotel hunted for gifts and sweets to celebrate the Sinhalese and Tamil New Year Thursday. At least 30 people were injured in the mid-morning blast, which flattened the hotel and four neighboring shops, the officials said, speaking on condition of anonymity.