U.N leader "Ban Ki-moon" on Monday started sending out invitations to a Syria peace conference on January 22, but Iran was not on the first list.
U.N deputy spokesman "Farhan Haq" said that U.S Secretary of State "John Kerry" and Russian Foreign Minister "Sergei Lavrov" will meet on January 13 in a bid to decide on whether Iran should take part, adding " Iran was not among the first invitations".
It was not known if UN envoy "Lakhdar Brahimi" would be at the January 13 meeting.
Russia has pressed for Iran's participation in the bid to end the 34-month-old conflict.
Ban has also spoken out in favor of Iranian involvement, but the United States and other western nations have opposed a frontline place for Tehran at the meetings in Switzerland.
The January 22 meeting is to help implement a June 2012 Geneva declaration by the major powers, including Russia and the United States, that a transitional government be established in Syria.