UPDATE 2-Clinton says Obama can't stand the heat

(Adds Obama quotes at Philadelphia rally, paragraphs 11-14)

By Jeff Mason

RADNOR, Pa., April 18 (Reuters) - Democratic presidential contender Hillary Clinton said on Friday that rival Barack Obama could not stand the pressure of the White House after the Illinois senator complained about tough questions at a debate.

Clinton said Obama's complaints about questions posed to him in their televised debate on Wednesday night raised doubts about whether he was tough enough to stand up to the scrutiny of the presidency.

The debate questions, which focused on a series of controversies and comments involving Obama, drew complaints on Thursday from the Illinois senator and from viewers.

"I know some of my opponent's supporters and my opponent are complaining about the hard questions," Clinton, a former first lady, told a rally.

"Well, having been in the White House for eight years and seeing what happens in terms of the pressures and the stresses on a president, that was nothing," she said.

Referencing a famous quote from folksy former Democratic President Harry Truman, Clinton said: "I'm with Harry Truman on this. If you can't stand the heat, get out of the kitchen."

Clinton, who has complained about moderators' treatment of her in previous debates, is in a hard fight with Obama for the Democratic presidential nomination to face Republican John McCain in November's presidential election. The two face off next in an important primary vote in Pennsylvania on Tuesday.

Obama spokesman Bill Burton accused Clinton of hypocrisy.

"Considering the fact that Senator Clinton sat on stage at the last debate and complained to all of America that she always gets the first question, her blatant hypocrisy here is stunning," he said in a statement.

The Clinton campaign has often accused reporters of being harder on her than they are on Obama.

Obama fired back at Clinton at a rally on Friday evening in Philadelphia that drew 35,000 people, according to the director of security at the Independence Visitor Center. The rally was held outdoors in front of the center.

Calling her a "tenacious opponent," Obama said Clinton's message is that nothing can change "say-anything, do-anything, special interest-driven" politics in Washington.

"Her message is, 'The Republicans have been doing this stuff over the last two decades, and I've learned how to play the same kind of game, so you might as well elect me because we can't expect significant change in Washington,'" he said.

He also accused her of a strategy of negative attacks, "which she defends by telling us that this is what the Republicans would do."