The campaigns of Sens. Hillary Rodham Clinton (D-N.Y.) and Barack Obama (D-Ill.) clashed over the candidates' foreign policy experience in dueling conference calls Sunday, days before critical primaries in Ohio and Texas.

"This is a strong woman who could be a great commander-in-chief," said Rep. Joe Sestack (D-Pa.), a former admiral.

Several of the officials also referenced the theme of Clinton's recent ad "Children," in which viewers are asked which candidate they'd most want to be in the White House to receive an important middle-of-the-night call on national security.

"There's no time to learn," retired Admiral Bill Owens told reporters. "The phone rings, and you have to be ready."

Polls show voters see the economy as the top issue this primary season, but Clinton in recent days has repeatedly sought to make foreign policy experience the central issue of the campaign. She does so ahead of what could be her last stand in Texas and Ohio, whose contests follow 11 consecutive victories for Obama.

On the Obama call, senior foreign policy advisers to the Illinois senator sought to contrast their candidate's judgement with Clinton's. They cited her vote in favor of the resolution backing the Iraq war to make the case that her foreign policy judgement is questionable.

"Anyone with any experience would know that you can't expect to go into that part of the world and be greeted as liberators," said Lawrence Korb, a former assistant secretary of defense who is advising Obama.

Susan Rice, another foreign policy adviser to Obama, said Clinton has questioned Obama's readiness "without offering any basis for her own experience."

"That assertion has to be backed up by a record of judgment," Rice said.

Polls show tight races in both Texas and Ohio. Rhode Island and Vermont voters will also go to the polls Tuesday, with pundits and political observers saying Clinton needs a big day to be able to stay competitive with Obama.