VIENNA — World powers held a fourth round of highlevel talks Friday aimed at bringing the United States back into the nuclear deal with Iran, with both sides signaling a willingness to work out the major stumbling blocks.

The talks began in Austria in early April. Russian delegate Mikhail Ulyanov tweeted following Friday’s meeting that “the participants agreed on the need to intensify the process.”

The U.S. pulled out of the landmark 2015 deal in 2018 after then-President Donald Trump said the pact needed to be renegotiated. President Joe Biden says he wants to rejoin the deal, known as the Joint Comprehensive Plan of Action, but that Iran needs to return to compliance.