WASHINGTON (AP) — Democratic support for Chuck Hagel's nomination for defense secretary grew on Thursday as the former Republican senator allayed concerns about his past statements on Israel and Iran.

Sens. Frank Lautenberg of New Jersey, Joe Manchin of West Virginia, Chris Coons of Delaware and Jeanne Shaheen of New Hampshire said they met with Hagel this week and were reassured by his commitment to Israel's security.

Hagel would replace Defense Secretary Leon Panetta, who is stepping down. Despite early misgivings, about a dozen Democrats have announced they would vote for his nomination, and none has declared opposition to President Barack Obama's choice.

Six Republicans have said they would vote against Hagel, with some stating their opposition before Obama announced his pick on Jan. 7.

"Senator Hagel clarified his position on Iran sanctions and Israel, and I am confident he is firmly committed to ensuring a strong U.S.-Israel relationship," Lautenberg said, adding that he and his colleagues will be watching closely "to ensure that issues of concern do not emerge as he takes on this critical position."

Separately, 13 former secretaries of defense and state as well as national security advisers sent a letter to members of the Senate strongly endorsing Hagel. Among them was former Defense Secretary Robert Gates, who has worked for Republican and Democratic administrations, and George Schultz and Brent Scowcroft, veterans of GOP administrations.

"For those of us honored to have served as members of a president's national security team, Sen. Hagel clearly understands the essence and the burdens of leadership required of this high office," the former officials wrote.

Hagel, who served two terms as Nebraska senator, has faced opposition from GOP-leaning outside groups over his past statements about the power of the "Jewish lobby" of pro-Israel groups and his doubts about the effectiveness of unilateral sanctions on Iran.

Not one GOP lawmaker has endorsed the nominee. Sen. John Barrasso, R-Wyo., writing in an op-ed in The Wall Street Journal on Thursday, all but announced his opposition.

"When we are faced with unpredictable national security crises, we can't afford to have a secretary of defense who has unpredictable judgment," Barrasso wrote.

Other lawmakers have said they are waiting for Hagel's confirmation hearing next Thursday in the Senate Armed Services Committee.

Democrats hold a 55-45 edge in the Senate and would have the votes to confirm Hagel. Continued...