A district court ruled Friday that four suspects in an alleged plot to attack the US or Israeli Embassy in Oslo should remain in jail for another month while police continue their investigation. The men were arrested last month on suspicion of firing gunshots at Norway's main Jewish synagogue on September 17. No one was hurt in the attack, in which about a dozen shots were fired at the building before dawn. The charges against all four men were strengthened to plotting terrorism, based on a police recording of two of them talking about ways to attack either the US or Israeli embassy. All men deny the charges, and their attorneys say there is no evidence their clients took any steps to prepare an attack.