DETROIT -- General Motors Co. and Chrysler Group LLC, bailed out by the United States in 2009, negotiated Thursday with the United Auto Workers for four-year labor deals after failing to meet a deadline Wednesday to reach new accords.

The union, which pledged not to strike either automaker, continued negotiations with GM and Chrysler. While GM and the UAW didn't set a new deadline for an agreement or turning to binding arbitration, Chrysler Chief Executive Officer Sergio Marchionne offered in a letter to UAW President Bob King to let teams negotiate for one more week.

Mr. Marchionne criticized Mr. King for not meeting with him Thursday night to settle the final economic issues. The deadline had been known since they pleaded together for government aid, he said. While Chrysler is the third-largest U.S. automaker, its 26,000 employees are "more relevant" than larger social issues that are "close to your heart," Mr. Marchionne said.

"You and I failed them today," the Chrsyler chief wrote in the letter obtained by Bloomberg News. "We did not manage to agree to a set of simple conditions that would have given certainty and peace of mind to 110,000 actives and retirees."

The UAW represents 111,000 production employees at Chrysler, GM, and Ford Motor Co. The Detroit-based UAW and Ford agreed Tuesday to extend their contract while negotiations continue.

Talks may have stalled over the amount of the signing bonuses or the union's desire to raise entry-level wages, said Arthur Schwartz, president of Labor & Economics Associates, a consulting firm in Ann Arbor, Mich. If the union settles too quickly, the membership may think that negotiators didn't fight hard enough and vote against a tentative agreement, he said.

"It makes no sense for the union to settle early because they never get everything they want," Mr. Schwartz said.

The UAW proposed signing bonuses of $8,000 to $10,000 for each member, four people familiar with the discussions said last week. Michele Martin, a spokesman for the UAW, has denied the union is seeking such large bonuses.

Talks seem to indicate that GM is the target company, and an agreement there is likely to set a pattern for Chrysler and Ford.

Mr. Marchionne said in his letter that he flew back from the Frankfurt motor show to complete a new labor deal. Mr. King couldn't be present because of "competing engagements," the letter said. The two sides were down to a few issues, "primarily involving the economics of our employees for the next four years," the Chrysler CEO said.

Mr. Marchionne, who is also CEO of Fiat SpA, expressed his frustration that the UAW and Chrysler, which required U.S. government assistance to get through its 2009 bankruptcy, couldn't come to terms after negotiating since July.

"We argued and pleaded, together, to be given a second chance to put Chrysler right," Mr. Marchionne wrote in the letter. "And we even agreed that, were we still around in 2011, that we would not go back to the old adversarial and confrontational ways of the past to resolve unsettled matters. Until now, there have been encouraging signs of a new paradigm governing the relationship between us."

UAW members at GM and Chrysler agreed to a strike ban for these negotiations as part their U.S.-backed bankruptcies. Any unresolved issues are subject to binding arbitration.

First Published September 16, 2011, 3:33 a.m.