President Obama will speak at the United Nations General Assembly meeting next Tuesday, an annual visit that will attract greater attention this year amid U.S. efforts to disarm Syria's chemical weapons and speculation about renewed talks with Iran.

Obama will have a chance to greet new Iranian President Hassan Rouhani at his debut U.N. gathering. The White House has said Obama is open to sitting down with Rouhani, which would mark the first meeting between U.S. and Iranian presidents since 1979.

“It's possible, but it has always been possible,” White House spokesman Jay Carney said Thursday about the possibility of an Obama-Rouhani meeting. “The extended hand has been there from the moment the president was sworn in.”

Rouhani is also scheduled to speak at the U.N. on Tuesday and both leaders’ speeches will be closely scrutinized for any shifts in style or positioning.

Iran has made a concerted effort to tone down its rhetoric since Rouhani took office in August, and he has promised not to use Iran’s nuclear energy program to develop weapons.

The UN meeting offers a major opening for the new leader. His predecessor Mahmoud Ahmadinejad regularly delivered combative speeches, leading U.S. and Israeli officials to walk out.

Early Friday, Rouhani penned an op-ed in the Washington Post calling for “constructive” dialogue.

“I urge my counterparts to seize the opportunity presented by Iran’s recent election,” he wrote. “I urge them to make the most of the mandate for prudent engagement that my people have given me and to respond genuinely to my government’s efforts to engage in constructive dialogue.”

The White House and other top administration officials have cautiously welcomed the shift but say Rouhani's commitment to dropping its pursuit of nuclear weapons will be judged by deeds, not words.

Some of Obama's critics say his decision to halt a planned strike on Syria after Assad crossed a “red line” by using chemical weapons will only embolden Iran, which is a much bigger threat to U.S. interests.

The U.S., U.N. and European Union have instituted sanctions on Tehran over fears it is developing nuclear weapons. But Iran insists its nuclear program is for peaceful energy purposes only.

Iran's leaders are pursuing a swift agreement to end the sanctions, seizing on a recent letter from Obama to the new leader last month that promised relief from sanctions if Tehran demonstrated a willingness to “cooperate with the international community, keep your commitments and remove ambiguities,” according to a report in the New York Times.

“We’ve seen a number of comments over the last several weeks from the Iranian regime,” White House spokesman Josh Earnest said Friday. “We welcome those comments as they do indicate a willingness to act constructively, to work constructively with the international community. But the fact of the matter is, actions are what are going to be determinative here.”

Obama’s speech to the U.N. gives the president an opportunity to respond to critics who say his response to Syria has been weak and inconsistent, and reduces its leverage with Iran. It will also give Obama a chance to rally international support against Assad if he fails to agree to a deal to turn over his chemical arsenal.

Secretary of State John Kerry on Thursday said the United Nations Security Council must act next week to pass a binding resolution calling for the destruction of Assad's chemical stockpile.

“Now the test comes,” Kerry said. “The Security Council must be prepared to act next week.”

Last week, Kerry reached an agreement with his Russian counterpart to have the Assad regime itemize its chemical weapons and agree to destroy all of them by mid-2014.

But in the days since, Russian leaders have continued to suggest that Syrian anti-government rebels – not Assad – was responsible for an August chemical attack that drew condemnation from the U.S. and its allies.

The U.S. gave in to Russian demands that any U.N. resolution dealing with Syrian chemical weapons not contain the threat of military force if Assad does not comply with the agreement.

But U.S. officials have said military strikes are still on the table if Syria fails to comply.