Tehran and Washington are reviewing fresh proposals from mediators on how to resolve their differences and avoid a return to all-out war, according to a diplomat briefed on the matter, after limited US airstrikes overnight.

Top security officials from Saudi Arabia, Pakistan and Turkey met Iranian leaders in Tehran on Monday, an effort to defuse tensions and revive talks aimed at preventing another round of US-Israeli strikes on the Islamic Republic.

The US ordered the departure of some diplomats and their families from Saudi Arabia due to the threat from Houthi militants, as the Iran-backed group carried out more deadly strikes from Yemen.

Three Saudi Arabian citizens were killed and others were injured in two attacks on the main airport in the capital, Riyadh, on Thursday, Saudi authorities said, as the kingdom faces intense fire from the Houthis.

Saudi Arabia is pumping 5.8 million barrels a day through its key cross-country pipeline, Energy Minister Prince Abdulaziz bin Salman said.

Yemen’s internationally-recognized government, backed by Saudi Arabia, claimed to have regained territory from the Houthis, as fighting in the region near the Bab el-Mandeb strait intensifies.

Yemen’s internationally recognized government launched a full-scale military campaign to recapture Houthi-held territory after weeks of escalating conflict between the Iran-backed group and Saudi Arabia.

Saudi Arabia halted several energy facilities in the south, as the Iran-backed Houthi militants claimed fresh strikes on the kingdom.

Yemen’s Houthi militant group targeted a Saudi Arabian supertanker sailing through the Red Sea.