DUBAI, United Arab Emirates — Middle East countries scrambled Tuesday to mediate the deep rift between Qatar and several other Arab nations that is threatening to splinter the U.S.-backed regional alliance.

Qatar’s neighbors, Saudi Arabia, United Arab Emirates and Bahrain were joined by Egypt Monday cutting ties with Qatar and denouncing it for supporting terrorism in the region.

The eruption of the long simmering dispute into an open rift shocked the region and has threatened the deeply intertwined regional trade links and air routes.

Turkish President Tayyip Erdogan spoke by phone with the leaders of Saudi Arabia, Kuwait and Qatar about resolving the dispute. Turkey enjoys good relations with the parties in the conflict.

“President Erdogan has initiated diplomatic effort to resolve this dispute between friends and brothers in line with the spirit of the holy month of Ramadan,” presidential spokesman Ibrahim Kalin said in a statement.

Kuwait also has signaled that it is ready to step in and try to heal the festering rift that threatens to blow apart the region.

Kuwait’s state news agency said that the country’s leader, Sheikh Sabah al-Ahmed al-Jabr al-Sabah, had spoken both with the Saudis and the leader of Qatar urging restraint.

In response to the Kuwaiti leader’s urging, Sheikh Tamim Bin Hamad al-Thani of Qatar agreed to postpone a speech about the crisis to await the result of the mediation, the peninsula nation’s foreign minister told the Al Jazeera news network.

Sheikh Mohammed bin Abdulrahman al-Thani added that no retaliatory measures would be taken against the Gulf countries and expressed hope that differences could be resolved through dialogue.

Flights to Qatar by the four Arab countries have been canceled, as have all land and sea links. Many Qatari flights transit through the neighboring countries, as do some of its exports like aluminum.

The feud, the most serious in decades among the Persian Gulf monarchies, has been simmering for years as Qatar has sought to project its influence across the region, including backing the Muslim Brotherhood and Islamist fighters in Libya and Syria. But the flaring tensions raised fears of another destabilizing conflict in a region already grappling with three civil wars and Islamist militant insurgencies on several fronts.

The diplomatic break also complicated U.S. efforts to rally Arab and Muslim leaders to form a united front against Sunni extremists and Iranian influence. That had been the principal reason for Trump’s visit to Riyadh, the Saudi capital, last month, a trip that the president and his allies had hailed as a success.