President Jacques Chirac warned Thursday of possible sanctions against Syria if its president refuses to cooperate with an investigation into the assassination of former Lebanese Prime Minister Rafik Hariri. The international community "will have to move to another stage, which is sanctions" if Syrian President Bashar Assad "persists in not wanting to listen or understand," Chirac said. "It is not conceivable, admissible, acceptable for the international community...that Syria refuses to cooperate," the French president said. Chirac spoke after meeting with Spanish Prime Minister Jose Luis Zapatero, who joined Chirac in insisting that Damascus abide by demands to cooperate with United Nations investigators. A UN commission is trying to determine who was behind the Feb. 14 truck bomb attack in Beirut that killed Hariri and 20 other people. An interim report pointed to Syrian and Lebanese intelligence services and accused Syria of limiting its cooperation.