VATICAN CITY (CNS) -- As the world braced for Iran to retaliate for the assassination of a Hamas leader who was staying in the Iranian capital, the Vatican secretary of state pleaded with Iran's new president not to escalate the Middle East conflict.

Cardinal Pietro Parolin, Vatican secretary of state, spoke by telephone with Iranian President Masoud Pezeshkian early Aug. 12, according to Matteo Bruni, director of the Vatican press office.

The cardinal, Bruni said, "expressed the Holy See's serious concern about what is happening in the Middle East, reiterating the need to avoid in any way the widening of the very serious ongoing conflict and opting instead for dialogue, negotiation and peace."

Cardinal Parolin congratulated Pezeshkian on his election in July, Bruni said, and also discussed "issues of common concern" with him.

Iran's official news agency, IRNA, had quoted Pezeshkian Aug. 4 as saying the killing July 31 of Hamas leader Ismail Haniyeh, who was in Tehran for Pezeshkian's inauguration, was a "big mistake" and "will not go unanswered." Israel was assumed to have been behind the killing.

Pope Francis, who consistently has called on Israel and Hamas to agree to a cease-fire, for Hamas to release the hostages it captured in October and for Israel to allow humanitarian aid into Gaza, also has been pleading for caution and restraint since the death of Haniyeh and Israel's acknowledged killing a day earlier of Hezbollah commander Fouad Shukur in an airstrike in a Beirut suburb.

"I am following with great concern what is taking place in the Middle East, and I hope that the conflict, already terribly bloody and violent, will not spread even further," the pope had said Aug. 4.

Three days later the pope said he wanted to "reiterate my appeal to all the parties involved so that the conflict does not spread and there may be an immediate cease-fire on all fronts, starting with Gaza, where the humanitarian situation is dire and unsustainable."