Newspaper market statistics put Obama's endorsement tally at 55and McCain's at 16 as of Saturday.

The newspapers reach a circulation of 5.8 million for Obama and1.5 million for McCain.

Obama picked up the backing of several major dailies, including the Los Angeles Times, The Washington Post and the Chicago Tribune, which has never endorsed a Democratic nominee for president.

In endorsing the senator from Illinois, his home-town newspaper wrote that it has observed his political rise from the front lines and can vouch for his ability.

The Washington Post emphatically endorsed him as "the right man for a perilous moment."

The Los Angeles Times said Obama "represents the nation as it is, and as it aspires to be."

The San Francisco Chronicle also endorsed the Democratic nominee, describing him as a "portrait of calmness and deliberation" throughout the financial crisis.

Other major endorsements for Obama include those of The Boston Globe, the St Louis Post-Dispatch, the Toledo Blade, the Pittsburgh Post-Gazette, The Seattle Times and Seattle Post-Intelligencer and the Nashville Tennessean.

Meanwhile, Republican nominee McCain has racked up some prominent endorsements over the past several weeks, including the New York Post, the Union Leader in New Hampshire, the Boston Herald and the Examiner newspapers.