WASHINGTON, April 30 (UPI) -- More than 80 congressional superdelegates haven't endorsed a U.S. presidential candidate but insiders said support is tilting toward Sen. Barack Obama, D-Ill.

Several superdelegates -- elected and party officials -- told the Politico, a Washington publication, most of the undecided senators and representatives have indicated their leanings to the campaigns of Obama and Sen. Hillary Clinton, D-N.Y.

"The majority of superdelegates I've talked to are committed but it is a matter of timing," said Sen. Claire McCaskill, D-Mo. "They're just preferring to make their decision public after the primaries are over."

Obama has an 18-13 lead among committed superdelegates in the Senate, while Clinton holds a 77-74 lead in the House of Representatives, the Politico said.

Don't count those "commitments" yet, Clinton spokesman Phil Singer said. Most of the uncommitted superdelegates are concerned about Obama's electability and look favorably on Clinton's winning states "Democrats must carry if we are to be successful in November," he said.

"Considering the rough patch Senator Obama is going through, it's understandable that Senator McCaskill would want to change the subject," Singer told the Politico, "but her observations don't jibe with what automatic delegates are actually saying."