Syria will not attend a Middle East peace conference set for next month unless the Israeli-occupied Golan Heights are on the agenda, President Bashar al-Assad said in comments broadcast on Monday.

"If they don't talk about the Syrian occupied territory, no, there's no way for Syria to go there," Assad told the BBC, referring to the Golan Heights, which Israel captured from Syria in the 1967 Arab-Israeli war.

"It should be about comprehensive peace, and Syria is part of this comprehensive peace. Without that, we shouldn't go, we wouldn't go."

In Washington, State Dept spokesman Tom Casey declined direct comment on Assad's views about the upcoming conference but he said the State Department would send out invitations at "an appropriate time," including to Arab League members such as Syria.

"Obviously it would be up to each individual country to decide at that point whether they want to attend or not," Casey told reporters.

The conference is expected to take place in Annapolis, Maryland not before mid-November, but U.S. officials say an exact time and venue have not yet been pinned down.

"It will take place sometime later this fall," said Casey.

Israel said it had no objections to Syria participating in the conference but it made clear that the focus should be on the Israeli-Palestinian track.

"We want Arab states there to support Israeli-Palestinian peace," said Israeli Foreign Ministry spokesman Mark Regev.

The United States is trying to organize a peace conference in November to be attended by Israel, the Palestinians and other Arab states, with the main focus on Palestinian statehood.

Assad said he was prepared to discuss peace initiatives, but only if the terms of the discussion were clearly defined.

"I don't see where the purpose and the substance of this conference (is)," he said.

"What are they going to talk about? What's the criteria? What (are) the methods and means? Everything is not clear.

"It needs more clarification for Syria to make a decision."

In the interview, Assad also would not rule out a military response to an Israeli air raid on its territory last month.

"It is possible, but we don't say that this is the option that we are going to adopt now. We said we have many different means... Retaliate doesn't mean missile for missile and bomb for bomb. We have our means to retaliate...

"It's always an option, that's why you have the army to defend your territory. We don't build (an) army to make any aggression, but to defend our country."

Israel is widely believed to have carried out an air raid against Syria on September 6. Some reports suggested that the raid may have targeted a military site linked to the production of weapons of mass destruction while others said it struck Iranian arms bound for the Lebanese Hezbollah guerrilla movement.

One report said the Israeli raid was aimed at testing new Syrian air defenses.

Israel has steadfastly refused to comment or to confirm what sort of operation it carried out, if any.

Diplomats in Damascus say, however, that at least four Israeli warplanes crossed into its territory, and some U.S. officials have linked the raid to Israeli suspicions of secret nuclear cooperation between Syria and North Korea.