BEIJING, March 1 (Xinhua) -- Iranian and U.S. officials have entered a critical week in negotiations to restart the 2015 nuclear deal, with major differences remaining on several key issues.

Iran said it refused to set a deadline for negotiations and that Iran's "red line" could not be breached.

  Iran's chief negotiator, Ali Bagheri Kani, arrived in Vienna on the morning of February 28, with positions at odds with those of Western negotiators, diplomats said, according to The Wall Street Journal. proved difficult to bridge.

  Western diplomats have warned that talks could collapse if a deal is not reached this week.

  According to the Iranian Islamic News Agency, Saeed Khatibzadeh, spokesman for the Iranian Ministry of Foreign Affairs, said at a press conference on the 28th that the draft agreement is ready, and 98% of the content is the joint efforts of all parties. but there are still individual issues that require political decision by Western countries, including the lifting of sanctions, the provision of "assurances" and some political accusations of Iran's peaceful nuclear activities.

  He re-emphasized that the Iranian side refused to set a deadline for negotiations.

Iran's "red line" cannot be broken through, and the West should not dwell on it too much.

  Over the past few days, Iran's Supreme National Security Council has held several meetings on the Iran nuclear talks in Vienna, and Iranian President Raisi also attended the meeting.

Iranian negotiators will be committed to promoting the settlement of outstanding issues.

During the negotiations, Iran has struggled to articulate its red lines and positions to the West.