The president of the U.N. General Assembly says he's "cautiously optimistic" about current attempts to broker a Syria peace deal because all powers with a stake in the conflict share the goal of defeating Islamic State extremists.

Mogens Lykketoft told The Associated Press Wednesday that he believes world and regional powers have a "narrow, but a very important common interest" in containing IS.

The talks are due to start next week, but could face delays because of disagreement over participants.

Lykketoft also says that he hopes the United Nations will for the first time elect a woman as its chief this year. Lykketoft is lobbying for more transparent selection of candidates for secretary general.

Lykketoft says a woman as the world's top diplomat "would be a brilliant idea."