The chief of Palestinian militant group Hamas said his organization is prepared to cooperate with the U.S. in promoting a peaceful resolution to the Arab-Israeli conflict if the White House can secure an Israeli settlement freeze and a lifting of the economic and military blockade of the Gaza Strip.

Khaled Meshaal, 53 years old, said in a 90-minute interview at Hamas's Syrian headquarters that his political party and military wing would commit to an immediate reciprocal cease-fire with Israel, as well as a prisoner swap that would return Hamas fighters for kidnapped Israeli soldier Gilad Shalit.

He also said his organization would accept and respect a Palestinian state based on 1967 borders as part of a broader peace agreement with Israel—provided Israeli negotiators accept the right of return for millions of Palestinian refugees and the establishment of a capital for the Palestinian state in East Jerusalem.

That pledge falls short of recognizing Israel, a necessary step for Hamas to be included in peace talks, but many Middle East diplomats said it could mark an important step toward that goal.

"Hamas and other Palestinian groups are ready to cooperate with any American, international or regional effort to find a just solution to the Arab-Israeli conflict, to end the Israeli occupation and to grant the Palestinian people their right of self-determination," Mr. Meshaal said.

A senior White House official said Mr. Obama's administration wouldn't respond to Mr. Meshaal's comments. Mr. Obama has said the U.S. would only hold direct talks with Hamas if it formally renounces terrorism and violence and recognizes the state of Israel. U.S. officials say that to engage directly with Mr. Meshaal would undermine the Palestinian Authority.

A spokesman for Israeli Prime Minister Benjamin Netanyahu on Thursday dismissed Mr. Meshaal's comments. "Anyone who has been following Khaled Meshaal's comments over the last few months sees clearly that despite some attempts to play with language in a cosmetic way to give the impression of possible policy moderation, he remains rooted in an extremist theology which fundamentally opposes peace and reconciliation," said the spokesman, Mark Regev.

Hamas in 2006 was elected to rule the Palestinian territories, but a global boycott, Israeli arrests and a 2007 civil war left the group in charge only of the Gaza Strip. Fatah maintains control of the West Bank, leaving the territories bitterly divided.

Mr. Meshaal said his movement is waiting for Mr. Obama and his special Middle East negotiator, George Mitchell, to present a broader outline for conducting Middle East peace talks.

Mr. Mitchell has focused on securing an Israeli settlement freeze in disputed areas in return for Arab states beginning to normalize their relations with Israel, such as establishing trade and telecommunications links.

"If Israel doesn't accept a halt to stop building settlements, what then?" Mr. Meshaal said, seated under photos honoring fallen Hamas leaders and Jerusalem's al Aqsa mosque. "The end of the settlements is a necessary step, but it's not the solution itself."

Mr. Meshaal's conciliatory positions toward Washington come amid significant political shifts in the region that are affecting Hamas's principal allies.

This week, Mr. Mitchell met Syrian President Bashar Assad in Damascus and agreed to begin easing U.S. sanctions as part of a growing diplomatic rapprochement between the two rivals. In June, Hezbollah, the Lebanese political party and militia, failed in its bid to gain political power through elections in Beirut. And Iran's government—Hamas's chief arms supplier and financier—has been subsumed in a post-election struggle that could lessen Tehran's ability and willingness to project itself into the Arab-Israeli conflict.

Some Middle East analysts and Western diplomats said these events could be feeding into Hamas's conciliatory line.

Syrian officials said this week that they've been advising Hamas to play a more constructive role in Arab-Israeli talks. They specifically cite Hamas's recent offer to enter into a long-term truce with Israel. "We believe Hamas has evolved," Syria's deputy foreign minister, Fayssal Mekded, said Monday. "They are for building and developing a Palestinian state."

A number of Middle East experts say Hamas's willingness to accept the 1967 borders represents a quasi-recognition of the state of Israel, though the militant group hasn't formally taken this step.

Hamas's 1988 political charter formally calls for the destruction of Israel and the creation of a Palestinian state on the lands that currently make up the Palestinian territories and Israel. The organization is designated a terrorist organization by the U.S., Israel and the European Union because of its use of suicide bombers against Israeli citizens and military personnel.

The "Quartet" of bodies seeking to broker Arab-Israeli peace talks, which includes the U.S., EU, United Nations and Russia, has refused to collectively engage Hamas in the process until it formally recognizes Israel's right to exist, and renounces terrorism and violence. Russia has been holding bilateral talks with Hamas.

Mr. Meshaal's conflict with Israeli authorities is also personal. In 1997, Mr. Netanyahu ordered the assassination of Mr. Meshaal in Jordan and Mossad agents sprayed a lethal toxin into the Hamas official's ear that began shutting down his respiratory system. The late Jordanian monarch, King Hussein, intervened and forced Mr. Netanyahu to dispatch an antidote by threatening to end Jordan's peace treaty with Israel.

In the interview, Mr. Meshaal offered both conciliation toward the U.S. and the West, and enmity toward Israel and its leadership. "I don't care about Israel—it is our enemy and our occupier and it commits crimes against our people," he said. "Don't ask me about Israel, Israel can talk for itself."

In recent months, a number of leading European politicians and U.S. foreign-policy luminaries, including former U.S. national security advisers Brent Scowcroft and Zbigniew Brzezinski, have called on Hamas to be formally brought into the peace process.

Critics of engaging Hamas, including senior members of the Obama administration, are wary of Mr. Meshaal's statements of accepting a Palestinian state along the 1967 borders.

Palestinian Authority leaders attacked Mr. Meshaal Thursday, saying Hamas was moving arms into the West Bank and trying to launch a "coup" in the territory.

Mr. Meshaal said Hamas wouldn't be an obstacle to peace. "We along with other Palestinian factions in consensus agreed upon accepting a Palestinian state on the 1967 lines," Mr. Meshaal said. This is the national program. This is our program. This is a position we stand by and respect."