The UN's Mideast envoy strongly urged Lebanon and Syria Friday to demarcate their borders and establish diplomatic relations as a way of reducing tensions between the two Arab neighbors. Speaking to reporters in Beirut, the envoy, Terje Roed-Larsen, said it was paramount for leaders of the two countries to agree on their shared borders, a reference to the disputed Shaba Farms area on Lebanon's southern border. Lebanon claims Shaba Farms, which has been controlled by Israel since it captured the Golan Heights from Syria in the 1967 Arab-Israeli war, but the United Nations says Shaba is Syrian and that Syria and Israel should negotiate its fate. Syria says the farms are Lebanese, but has yet to present the UN with documents to back that claim. "It is now the time, and urgently, for the parties to sit down and decide, and whatever the outcome is we will support it," Roed-Larsen said after talks with Lebanese Foreign Minister Fawzi Salloukh. "I re-emphasize a border agreement cannot be done by the UN It can only be done by two sovereign states. Which means now it is urgent for representatives of the government of Syria and representatives of the government of Lebanon, to sit down and agree on that boundary," he said. The United Nations, he said, will lend all the support it can for such an exercise. Relations between Lebanon and Syria sharply deteriorated following last year's truck bombing in Beirut that killed former Lebanese Prime Minister Rafik Hariri. The killing sparked massive anti-Syrian protests in Beirut which, along with international pressure, forced Syria to withdraw its army from Lebanon, ending a 29-year-military presence. Lebanese leaders who have recently been conducting national dialogue talks agreed following a March 14 session to demand the establishment of Lebanese-Syria diplomatic relations. The two countries have never exchanged ambassadors since they gained independence from France in 1943. Many Lebanese believe Damascus refuses to establish diplomatic ties because it regards Lebanon as a part of their country illegitimately cut away under French rule. Roed-Larsen said tensions between Lebanon and Syria could only be defused through diplomatic channels. "The best way to do it is through civilized, normal diplomatic relations," he said. The UN envoy arrived in Lebanon on Thursday for talks on a UN Security Council resolution that calls on authorities to disarm Hizbullah and Palestinian terror groups. Hizbullah, which continues to attack Israel, refuses to disarm. Roed-Larsen also met with Druse leader and key anti-Syrian politician Walid Jumblatt. He is expected to also meet the prime minister, parliament speaker and Saad Hariri, son of the slain former prime minister. Roed-Larsen is due to submit next month a progress report on Resolution 1559 to UN Secretary-General Kofi Annan. He has over the past few days visited Saudi Arabia, Qatar, Egypt and Jordan.