VIENNA - The parties involved in Iran's nuclear talks may consider extension of the negotiation if time is not enough for a deal, Chinese Foreign Minister Wang Yi said here on Monday.

Wang said there are two possibilities -- one is that all the relevant parties might be able to "turn the corner" to work out a final comprehensive solution, and the other is prolonging the talks since the issue involves a lot of professional and technical aspects which need detailed discussions.

"If we don't have enough time here, I believe all the parties concerned will continue to think about whether we will be able to extend the duration of this negotiation and how long it will be extended," Wang told reporters in Vienna.

But the top Chinese diplomat hopes a deal on Iran's nuclear issue between Iran and the five permanent members of the U.N. Security Council plus Germany (the P5+1) could be reached by the Monday deadline.

As foreign ministers of the P5+1 are expected to meet here in hours, the sticking points are still how many uranium enrichment centrifuges Iran can have and the speed of lifting sanctions.

Earlier, Iran's semi-official Fars news agency reported that the nuclear talks may be extended again, saying the parties concerned have yet to reach consensus on the duration of this extension.

An unnamed official with the Iranian delegation also told the Iranian Students News Agency on Sunday that due to time limit and existence of many details yet to be discussed, it is impossible to agree on a comprehensive deal by Monday.

The P5+1 is holding talks with Iran in Vienna on the country's nuclear issue.

It is hoped that a comprehensive deal would be reached by Monday that would ensure Tehran's nuclear program is totally peaceful, while, in return, Western powers would phase out sanctions that have severely damaged the country's oil-dependent economy.

However, the parties concerned can not bridge the remaining major differences as the West wants Iran to significantly scale back its nuclear program, while Iran insists its nuclear right is inalienable.