LOS ANGELES (Reuters) - Wendy's International Inc (WEN.N: Quote, Profile, Research) said on Thursday that first-quarter sales at restaurants open at least 15 months fell at both franchised and company-owned locations, hurt by bad weather and an early Easter.

The hamburger chain operator reported same-store sales declines of 1.6 percent at company-owned restaurants and 0.1 percent at those owned by franchisees.

The results from company restaurants were worse than expected, UBS analyst David Palmer said in a client note.

"We believe the chain underperformed U.S. fast food trends in the quarter," said Palmer, who expects the restaurant segment to be up 1.5 percent for the quarter.

Dublin, Ohio-based Wendy's said Easter's shift into the first quarter cut same-restaurant sales at company-owned locations by 0.3 percent. Severe winter weather in the Midwest and northern United States during March also hurt sales.

Still, the company said sales trends improved in February and March, compared with January.

Wendy's directors have been weighing a sale of the company since June 2007 under pressure from billionaire investor Nelson Peltz, who has been pressing for a better financial performance.

Peltz, whose Triarc Cos Inc owns the Arby's chain, has offered to buy Wendy's and said he planned to seize control of the No. 3 U.S. hamburger chain's board.

Still, Palmer said, Wendy's board has remained mum on its plans.