Pakistan confirmed the arrival of a delegation of Iranian negotiators ahead of talks on Saturday with the U.S. to end the six-week-old war Washington and Tel Aviv have led against Tehran.

The negotiations will seek to cement a two-week ceasefire that began Tuesday but which has come under strain as Iran continues to block most shipping traffic through the Strait of Hormuz, the world’s most critical chokepoint for oil and gas supplies.

Pakistan’s foreign ministry said the Iranian delegation led by parliamentary speaker Mohammad Bagher Ghalibaf and Foreign Minister Abbas Araghchi arrived in the capital Islamabad late Friday.

Pakistan’s Deputy Prime Minister and Foreign Minister Mohammad Ishaq Dar “expressed the hope that parties would engage constructively, and reiterated Pakistan’s desire to continue facilitating the parties towards reaching [a] lasting and durable solution to the conflict,” Pakistan’s foreign ministry said in a post on X.

But question marks hang over the ceasefire and the outcome of the talks. Ghalibaf warned Friday that scheduled negotiations to end the war with the United States cannot begin unless Israel halts attacks on Lebanon and unless the U.S. releases Tehran’s frozen assets.