It will be impossible to stick to the Nov 24 deadline to reach a comprehensive agreement with world powers on Tehran's nuclear programme, a source said here Sunday.
"Considering the short time left until the deadline and number of issues that needed to be discussed and resolved, it is impossible to reach a final and comprehensive deal by Nov. 24," the source with the negotiating team told Iran's Students News Agency, Xinhua reported.
Some media reports said Iran was considering extending the time of the talks by up to a year.
"The issue of extension of the talks is an option on the table and we will start discussing it if no deal is reached by Sunday night," the source said.