With little more than 100 days left in office for UN Secretary General Kofi Annan, the UN Security Council aims to whittle down a seven-candidate list in another informal vote on Thursday, reported dpa. Part of the winnowing process will likely entail the use of veto power by the five permanent members, diplomats said. After two so-called straw votes since July, South Korean Foreign Minister Ban Kimon leads in the race. But those ballots gave equal power to all 15 members on the Security Council, dragging down the search process for a successor to Annan, who will step down on December 31 after a 10-year tenure. US Ambassador John Bolton has proposed that the permanent members - the US, China, Britain, Russia and France - use their veto power on Thursday to narrow the field. "We have reached the time in the decision-making process, both for the candidates and the governments on the Security Council, that it would be useful to know where the permanent members and the non- permanent members stand," US Ambassador John Bolton said. Once the permanent members reach a decision on one or more candidates, the selection would move swiftly in the council, which would then recommend candidates to a final vote by the 192-nation UN General Assembly. In the last two straw polls, Ban Kimon led in the vote, followed by Sashi Tharoor of India, Thailand's Deputy Prime Minister Surakiart Sithirathai, Jayantha Dhanapala of Sri Lanka and Jordanian Prince Zeid Raad Zeid al-Hussein.