NEW YORK • Democratic presidential candidate Hillary Clinton has dismissed as ridiculous a charge by her rival Bernie Sanders that she is unqualified to be president, as tensions rise in the Democratic race.
During a rally in Philadelphia, Mr Sanders listed Wall Street donations to Mrs Clinton's campaign funds as well as her support for past trade deals and the war in Iraq as reasons that she did not meet the requirements for the job.
"She has been saying lately that she thinks I am not 'qualified to be president'," said the Vermont senator. "Let me just say in response to Secretary Clinton: I don't believe she is qualified if she is, through her super-PAC (fund-raising committee), taking tens of millions of dollars in special interests' funds."
His remarks followed statements by Mrs Clinton in which she questioned some of the answers he gave in a recent newspaper interview. He drew criticism on issues ranging from the Israeli-Palestinian conflict to breaking up too-big-to-fail banks.
Mrs Clinton said on Wednesday that it seemed like Mr Sanders "hadn't done his homework".
Hours after Mr Sanders' speech in Philadelphia, one of Mrs Clinton's senior aides, Ms Christina Reynolds, said his remarks were "a ridiculous and irresponsible attack for someone to make" against one of the most qualified candidates ever to run.
Mrs Clinton's allies and the White House also rose to her defence on Thursday.
While United States President Barack Obama has remained publicly neutral in the race, spokesman Eric Schultz told reporters that Mr Obama "has said that Secretary Clinton comes to this race with more experience than any non-vice-president" in recent history.
The two candidates are preparing for New York's Democratic primary on April 19, which comes after Mr Sanders has scored six wins in caucuses and primaries since the middle of last month, including a 13- point win in Wisconsin on Tuesday.
While both have taken pride in the fact that their contest has focused on issues rather than personal attacks, the latest salvos foreshadow a more negative phase heading into the New York primary.
A loss, or even a narrow win, in Mrs Clinton's adopted home state, which she represented in the US Senate, may raise questions about the strength of her support within the Democratic Party.
For Mr Sanders, New York's 247 delegates offer a last chance to narrow the long odds he faces in trying to catch up with Mrs Clinton in the nomination race.
A March 31 Quinnipiac University poll showed Mrs Clinton leading Mr Sanders in the state by 12 percentage points.