UPDATE 1-Clinton says Obama can't stand the heat

(Adds Obama spokesman, background; previous PHILADELPHIA)

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 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.