Lebanese Prime Minister Fouad Siniora has asked the United Nations to help Beirut investigate the assassination of Industry Minister Pierre Gemayel, U.N. Secretary-General Kofi Annan said on Wednesday (November 22). Siniora wrote to Annan on Tuesday (November 21) that his government wanted Gemayel's murder added to the ongoing U.N. inquiry into the February 2005 murder of former Lebanese Prime Minister Rafik al-Hariri, Annan told the Security Council in a letter asking it to "take appropriate action." Later in the day Annan spoke to reporters and said he was "Extremely worried about the situation in Lebanon." "The situation is delicate, it's very fragile and we should all do whatever we can to support the Lebanese people and the government and encourage them to stand united," said Annan. Lebanon braced on Wednesday for a bitter power struggle after the assassination of an anti-Syrian Christian cabinet minister which his allies blamed on Syria. Industry Minister Pierre Gemayel was gunned down on Tuesday as he drove in a Christian suburb of Beirut, becoming the sixth anti-Syria politician to be killed in nearly two years. The assassination is certain to heighten tensions in Lebanon amid a deep political crisis pitting the anti-Syrian majority against the pro-Damascus opposition led by Hezbollah, which is determined to topple what it sees as a pro-U.S. government. The United Nations said Serge Brammertz, who heads the Hariri probe, could decide on his own whether to assist Lebanese investigators, U.N. chief spokesman Stephane Dujarric said. But Annan forwarded Siniora's request to the Security Council to seek its guidance, Dujarric said. The U.N. investigation is already looking into 14 other apparently politically motivated attacks in Lebanon since Hariri's killing. Brammertz, who heads the commission, has reported evidence that all 15 cases were linked in some ways. Gemayel was killed after a Cabinet vote to tentatively approve U.N. plans for a new international court to try suspects in the Hariri murder and the 14 related cases. The Siniora Cabinet, where anti-Syrian ministers hold most seats, voted after the resignation of six opposition ministers in a manoevre seen by many in Lebanon as an attempt to block creation of the special court. Lebanon's pro-Syrian president, Emile Lahoud, protested that the Cabinet vote was illegitimate. But following Gemayel's murder, the Security Council pushed ahead on Tuesday with U.N. approval of the plan, which now requires formal approval from the Lebanese government. The latest assassination nonetheless pushed the Siniora government deeper into crisis. The death or resignation of two more ministers would bring it down. Several prominent anti-Syrian leaders have blamed Syria for Gemayel's murder and warned that more assassinations could be in the works. Damascus has denied any role in the Gemayel and Hariri assassinations.