Iran has reached a tentative agreement that six world powers will relieve sanctions for Tehran with any nuclear deal, addressing a huge stumbling block in the negotiations, according to the Associated Press.

However, the two parties will still have to sign off on the document outlining what sanctions are going to be lifted and when, according to the report that cited two unnamed diplomats.

The Associated Press reported that sanctions relief was one of the toughest issues of the negotiations, which missed the initial deadline and was extended to July 7.

The negotiations involve the five permanent members of the United Nations Security Council and Germany.

Secretary of State John Kerry said Friday that negotiations were "making progress" and that "we have a lot of work to do."