ConocoPhillips said it will extend efforts to sell its Trainer oil refinery because of "recent interest" from potential buyers.

"We are continuing efforts to seek a buyer," the Houston company said in an e-mail. Extending the sales deadline from March 31 to the end of May will "allow more time for discussions to take place."

ConocoPhillips shut the 190,000-barrel-per-day refinery in the Delaware County community last year and laid off about 400 employees there as of Jan. 31.

In January, ConocoPhillips said it intended to "permanently shut down" the Trainer refinery if it had not identified a buyer by the end of March.

Both ConocoPhillips and Sunoco Inc. have said they have not been able to operate their Philadelphia-area refineries profitably in recent years.

Sunoco idled its Marcus Hook refinery in December and intends to close its Philadelphia refinery by July 1 if it cannot find a buyer.

In early March, the owner of a Western Pennsylvania refinery said he was considering bidding on Sunoco's Philadelphia refinery. John A. Catsimatidis, chairman and chief executive of United Refining Energy Corp. had said his company would decide by the end of the month whether to make an offer.

Contact Mike Armstrong at 215-854-2980 or marmstrong@phillynews.com, or @PhillyInc on Twitter.