CAIRO (AP) — Mediators moved closer Wednesday to extending the ceasefire between the United States and Iran and restarting negotiations to salvage the fragile truce before it expires next week. A senior Iranian military official threatened to halt trade in the region if the U.S. does not lift its naval blockade, underscoring tensions that are overshadowing the diplomacy.

The U.S. blockade on Iranian ports and renewed Iranian threats have imperiled the week-old agreement, but regional officials said Wednesday they were making progress, telling The Associated Press that the United States and Iran had given an “in principle agreement” to extend it to allow for more diplomacy.

The commander of Iran’s joint military command warned Wednesday that Iran would completely block exports and imports across the Persian Gulf region, the Sea of Oman, and the Red Sea if the U.S. military does not lift its blockade on Iranian ports.

“Iran will act with strength to defend its national sovereignty and its interests,” said Ali Abdollahi, calling the blockade “a prelude to violating the ceasefire.” His comments were reported by Iranian state media.

Before the two-week ceasefire expires on April 22, mediators are pushing for a compromise on three main sticking points that derailed direct talks last weekend — Iran’s nuclear program, the Strait of Hormuz and compensation for wartime damages — according to one of the regional officials who is involved in mediation efforts.

Both officials spoke on condition of anonymity to discuss the matter.

World leaders including U.S. President Donald Trump and U.N. Secretary-General António Guterres said on Tuesday that revived talks in the upcoming days were likely.

The fighting has killed at least 3,000 people in Iran, more than 2,100 in Lebanon, 23 in Israel and more than a dozen in Gulf Arab states. Thirteen U.S. service members have also been killed.