SINGAPORE, Feb 22 (Reuters) - A liquefied natural gas tanker on Sunday docked at the Sabine Pass terminal in Louisiana, with only days to go before the United States ships its first export cargo of seaborne gas from the lower 48 states.

The Asia Vision LNG tanker docked at the Sabine Pass LNG terminal on Sunday, Reuters shiptracking data showed.

The tanker arrived in December in the Gulf of Mexico, but has been anchored off the coast of the terminal after the first shipment from the facility was delayed due to mechanical problems.

U.S. company Cheniere Energy said it expected its first cargo to leave the facility by the end of this month or in early March.

"We will export the first cargo shortly. Touch wood, it'll be at the end of February or in early March," Andrew Walker, Cheniere Energy's vice president for strategy, said during an energy industry event in Germany last week.

The Energy Atlantic LNG tanker, which was initially scheduled to pick up the first cargo from Sabine Pass, has also been sitting off the coast of the facility since January.

Once operational, Sabine Pass will be the first LNG export terminal outside of Alaska. The United States has been exporting LNG mostly to Japan from Alaska since 1969.

(Reporting by Jacob Gronholt-Pedersen and Henning Gloystein; Editing by Anand Basu)