Iran nuclear talks in Vienna have not reached a dead end, Iran's foreign ministry spokesman said on Monday during a news conference in Tehran, according to Reuters.

Saeed Khatibzadeh added that key issues that need political decisions are under discussion and a prisoner swap with the United States was on the agenda in parallel with the nuclear talks in Vienna.

"This issue is currently on the agenda in parallel with the Vienna talks.... But it seems that the U.S. has not made a decision on it. Perhaps it is waiting for the results of the talks," said Saeed Khatibzadeh.

The spokesman also said that Tehran had already taken its political decision by staying in the 2015 nuclear deal after Washington abandoned it in 2018.