A bomb exploded in front of the headquarters of Nepal\'s monopoly oil importer Monday, killing three people and injuring five in the capital\'s first major attack in four years, police said. The government heightened security in response, the Associated Press reported. Home Minister Bijaya Gachchedar said a little-known group calling itself United Ethnic Liberation Front took responsibility for the bombing. He said an emergency meeting of the security forces have been called and security has been heightened.