United Airlines and Continental Airlines in the US have been in talks for a possible alliance.

United has to make a decision soon whether to merge with US Airways, which has also been in discussions.

Continental Airlines, which called off merger talks with United in late April, is also in advanced alliance talks with American Airlines AMR Corp and British Airways.

The wave of talks has come after Delta Air Lines and Northwest Airlines Corp said in April they planned to merge and become the world's largest airline, seeking to counter skyrocketing fuel prices, a weak economy and growing competition from European carriers.