* British ambassador warns against obstructing transition
* Yemen says help needed to reach elections in 2014
* Yemen's security international priority
By Mohammed Ghobari
SANAA, Jan 27 (Reuters) - U.N. Security Council envoys flew to Yemen amid tight security on Sunday to show support for a U.S.-backed power transfer deal in danger of faltering and plunging the country back into chaos.
Ending political turmoil in Yemen is an international priority - it flanks oil producer Saudi Arabia and major shipping lanes and is struggling with multiple conflicts including an al Qaeda insurgency, a Shi'ite Muslim rebellion in the north and separatist forces in the south.
Britain's U.N. representative Mark Lyall Grant, speaking at a news conference in Sanaa after talks with President Abd-Rabbu Mansour Hadi, warned what he called a minority against spoiling reconciliation efforts in the Arab world's poorest country.
Witnesses said thousands of Yemeni troops backed by armoured vehicles and helicopters were deployed across Sanaa as the ambassadors arrived for the one-day trip. Grant said the visit was the first to Yemen by the Security Council and the first it had made for five years to the Middle East.
"We have noticed that a minority are trying to obstruct the political process," he said through a translator, adding that under U.N. Security Council Resolution 2014 the council had the power to take steps against those who blocked reconciliation.
He did not name anyone, but the political reforms being pursed by Hadi include restructuring the armed forces to weaken the influence of the family of his predecessor Ali Abdullah Saleh.
Saleh stepped down in February 2012 after 33 years in office under the U.S.-backed deal but he remains influential in the military and wider society. His continuing sway over Yemen worries Gulf neighbours and Western nations who fear the political transition could descend into chaos.
Efforts to convene a national reconciliation dialogue central to reform have met resistance from south Yemen separatist leaders who complain of discrimination by the north. Some are pressing for the revival of a separate southern state that merged with north Yemen in 1990.
Under the power transfer deal, Hadi is overseeing reforms for a two-year interim period to ensure a transition to democracy. Presidential and parliamentary elections are expected in 2014.
Yemen's Foreign Minister Abubakr al-Qirbi said the Security Council's visit was to "help Yemen reach the general elections in February 2014 ... They will not allow anyone to stop the wheels of change."
Speaking to reporters after talks with the envoys, Hadi said dialogue was the only way to resolve Yemen's problems and urged international donors to meet their financial pledges.
Members of a Yemen-based branch of al Qaeda have launched a series of bombings in the capital since its members and allies were ejected from strongholds they occupied in southern Yemen during the turmoil of 2011. (Reporting by Mohammed Ghobari, writing by Sami Aboudi and William Maclean; Editing by Janet Lawrence)