Democrat Barack Obama explained the roots of his unusual name, listed some of his Jewish friends and voiced support for Israel on Thursday during a synagogue visit designed to shore up Jewish support for his US presidential bid.

Obama, an Illinois senator and the front-runner for his party's White House nomination, has battled concerns among some Jewish Americans about his race, religion and views on Israel.

Obama addressed those issues in a nearly two-hour meeting with Democrats and Republicans at a Jewish temple in Florida, a state that will be key to winning November's general election.

"There is not a single trace of me ever being anything more than a friend of Israel and a friend of the Jewish people," Obama said, telling the crowd not to believe fliers and e-mails that suggested otherwise.

"Judge me by what I say and what I've done. Don't judge me because I've got a funny name. Don't judge me because I'm African-American."

Critics have raised doubts about Obama's commitment to the Jewish state and have floated rumours that he was a Muslim.

Obama, who is a Christian, said as president he would bring "an unshakable commitment" to maintaining the American-Israeli bond, a mainstay of US Middle East policy.

"If you get one of these e-mails that says I'm a Muslim: not true," he told the crowd.

The questions from the B'Nai Torah Congregation touched on Obama's policy proposals and his personal life. When asked about his name, Obama said it had the same roots as a similar Jewish one and meant "one who's blessed".

One questioner asked the Illinois senator to name close friends who were Jewish and pro-Israel.

"I hesitate to start listing them out," Obama said, cautioning against a stereotype that having acquaintances in a minority group meant you did not behave in a prejudiced way.

He then identified a handful of close Jewish friends and advisers.

IRAN, RACE

Questioners also drilled him on his willingness to meet with US foes like Iranian President Mahmoud Ahmadinejad, who has denounced Israel and denied the Holocaust occurred.

Obama, while critical of the Iranian president, said direct diplomacy with Iran would be more effective than no engagement. "I believe the policy of not talking to our enemies has not worked," he said.

Not everyone agreed.

"I think that our commander in chief should not propose talks with someone who calls for the destruction of Israel," Stephen Lippy, 51, told Reuters.

Some said they were concerned about Obama's support for the Jewish state before his visit but came away satisfied.

"I think today convinced me," said Aaron Levitt, 32, a rabbi and Democrat. "I feel like he made it very clear that Israel's at the centre of his Middle East policy and would be a very important ally in his presidency."

Obama, who would be the nation's first black president, addressed the issue of race directly, saying he was concerned that a historic connection between African Americans and Jewish Americans had slipped.

"I want to make sure that I am one of the vehicles by which we can rebuild those bonds," he said.

A sample of audience members said race would not affect their votes, while admitting it could be an issue for some.

"I think that people don't realise it, but I do think it's there," said Obama supporter Barbara Schneider, 55.

"As a Jew, would I vote for a black person? Sure," said Lippy. "But...my issue is will he be the best commander in chief when it comes to assisting Israel and our other Western democratic allies."