A car loaded with explosives and headed for a police station in northern Algeria exploded Tuesday after officers stopped the attack with bullets. At least three people were killed and 23 wounded, the Interior Ministry said. Officers opened fire on a vehicle that was speeding toward the local police station in the town of Thenia, 60 kilometers (40 miles) east of Algiers. The vehicle exploded short of the building, leaving a 2-meter-wide (6.5-foot-wide) crater. The explosion was the latest in a wave of attacks showing that Islamic fighters are regrouping in Algeria, where offensives by security forces and government amnesty offers had thinned the ranks of insurgents in recent years. Meanwhile, a report Tuesday said police had arrested four people allegedly involved in planning the most serious recent attack: twin suicide bombings Dec. 11 in the Algerian capital that killed at least 37 people, 17 of them U.N. workers.