SRI LANKA ? A bomb ripped through a crowded passenger bus near Sri Lanka’s capital during morning rush hour today, killing at least 21 people and wounding an additional 47, officials said.

The bombing was the second attack in three days targeting civilians. A blast targeting a passenger train wounded 18 passengers and bystanders in capital Colombo on Wednesday.

The country’s military blamed the attack on Tamil Tiger rebels, who did not immediately comment on the blast.