Li told reporters on Sunday in Vienna there won't be a long extension of Iranian nuclear negotiation.
He said it is possible to make a comprehensive deal on Iranian nuclear issue within one week, though many tough issues still needed to be resolved.
'Now it's time to make a vigorous effort. Not only the political will is required, but the political will must be put into action,' Xinhua reported while quoting Li as saying.
Iran, the European Union and representatives of the P5+1 have been holding intensive nuclear talks to reach a final agreement on Iran's nuclear issue.
Both sides are to find a solution for a nuclear dispute that goes back to over a decade.
Two sides' experts are still holding negotiations in Vienna.
While the negotiations to draft the text of comprehensive agreement are underway in the Austrian capital, the foreign ministers of some participating countries including Iran returned home for a short time.
The Iranian Foreign Minister Mohammad-Javad Zarif and his counterparts from the six world powers- the US, UK, France, Russia, China and Germany- agreed to re-fly to Vienna as soon as the talks witnessed progress.
Zarif returned home early on Monday and said he is to depart for Vienna on Tuesday.