“So it is my sincere hope that, when we meet, we will be able to set a date for the Geneva II [Roman numeral 2] meeting.”

More than 100,000 people have been killed in Syria, and more than 6 million more have been internally displaced or become refugees.

An appearance by Iran's newly elected president, Hassan Rouhani, is drawing pre-meeting buzz.

Many leaders will be keen to hear what Rouhani has to say, and whether he is ready to improve relations with the West and answer outstanding questions about his country’s suspect nuclear program.

Speculation has been growing about a possible encounter between U.S. President Barack Obama and Iran's new head of state during the U.N. meetings. However, White House officials say there are currently no plans for the two men to meet.

Rouhani has been on a diplomatic charm offensive, meanwhile, offering interviews to American media and taking a far softer line than his predecessor, Mahmoud Ahmadinejad, who was widely vilified in the West for doubting the Holocaust and questioning Israel's right to exist.

Ahmadinejad's fiery rhetoric at the U.N. often was boycotted by Western and Israeli envoys who staged walkouts.

Obama is scheduled to be the second speaker at the General Assembly's opening session on Tuesday, after Brazilian President Dilma Rousseff.

Rousseff was to have made a state visit to Washington next month, but canceled plans for the trip abruptly this week, following disclosures that the U.S. has spied on the Brazilian government's internal communications. That could make any encounter between the two leaders awkward.