PHILADELPHIA -- Sen. Barack Obama on Wednesday criticized former President Carter for planning to meet with leaders of the Palestinian militant group Hamas as he tried to reassure Jewish voters that his candidacy isn't a threat to them or U.S. support for Israel.

The Democratic presidential candidate's comments to a group of Jewish leaders were his first on Carter's controversial meeting scheduled this week in Egypt.

The presumptive Republican presidential nominee, Sen. John McCain, earlier in the week called on Obama to repudiate Carter's meeting.

Obama told the group he had a "fundamental disagreement" with Carter, who was rebuffed by Israeli leaders during a peace mission to the Middle East this week.

"We must not negotiate with a terrorist group intent on Israel's destruction," he said. "We should only sit down with Hamas if they renounce terrorism, recognize Israel's right to exist and abide by past agreements."

The Illinois senator has been working to reassure Jewish voters nervous about his candidacy after publicity about anti-Israel sentiments expressed by his former pastor, the Rev. Jeremiah A. Wright Jr., and criticism from his Democratic rival, Sen. Hillary Rodham Clinton, during a February debate that he hadn't immediately rejected an endorsement from black Muslim leader Louis Farrakhan. Obama responded that he already denounced Farrakhan, but would reject his support as well.

Obama told the group he had not been aware of Wright's more incendiary speeches before launching his presidential campaign last year, even though he had been a member of Wright's congregation for nearly 20 years. Obama said he had spoken to Wright and privately conveyed his concerns about some sermons once he learned of their content. But he acknowledged that he had declined to be more public in his criticism until recently, since Wright was soon to retire from ministry at Chicago's Trinity United Church of Christ.

"You make a decision about how are you going to handle it," Obama said. "Do you publicly denounce his comments? Do you privately express concern but recognize you are still part of a broader church community that is going to be transitioning? I chose the latter."

Obama has stepped up his outreach to the Jewish community in recent weeks after videos of Wright's speeches surfaced in which he criticized Israel and expressed sympathy for the Palestinian cause.