US President Donald Trump on Monday said that “interesting things are happening” on Middle East peace, following a phone call he held with the king of Saudi Arabia.

“Spoke yesterday with the King of Saudi Arabia about peace in the Middle-East. Interesting things are happening!” the US president wrote on Twitter.

It was not clear whether Trump was referring to the Israeli-Palestinian peace process, Saudi Arabia’s ongoing feud with its Gulf neighbor Qatar or speaking generally about the conflict-plagued region.

Since coming to office in January, Trump has prioritized finding a resolution to the Israeli-Palestinian conflict, which he has referred to as the “ultimate deal.” The US president has offered few specifics on how he plans to jump-start negotiations and bridge the mutual distrust between the sides, though he has repeatedly expressed optimism that he can help the the Israelis and Palestinians achieve an accord.

Reaching a two-state agreement has also long been a priority of the Saudis, who notably were the main backers of the 2002 Arab Peace Initiative, which promised Arab recognition of Israel in exchange for, among other conditions, a full withdrawal to the pre-1967 armistice line. Prime Minister Benjamin Netanyahu has said that he backs the “general idea” of the offer, but has never fully endorsed it.

In his phone call Sunday with the Saudi King Salman bin Abdulaziz Al Saud, Trump urged unity among the Gulf states and reiterated the importance of stopping terrorist financing and discrediting extremist ideology, according to the White House.

Trump also spoke with Crown Prince Mohamed bin Zayed Al Nahyan of Abu Dhabi and Emir Tamin bin Hamad Al Thani of Qatar on Sunday.

US President Donald Trump (C) and Saudi's King Salman bin Abdulaziz al-Saud (C-R) pose for a picture with leaders of the Gulf Cooperation Council in Riyadh on May 21, 2017. (AFP Photo/Mandel Ngan)

US President Donald Trump (C) and Saudi’s King Salman bin Abdulaziz al-Saud (C-R) pose for a picture with leaders of the Gulf Cooperation Council in Riyadh on May 21, 2017. (AFP Photo/Mandel Ngan)

Qatar on Monday responded to a list of demands from Saudi Arabia and its allies after they agreed to give a defiant Doha another 48 hours to address their grievances.

Details of the response were not immediately available, but a Gulf official told AFP that Qatari Foreign Minister Sheikh Mohammed bin Abdulrahman Al-Thani had delivered it during a short visit to Kuwait, which is acting as a mediator in the crisis.

Saudi Arabia, the United Arab Emirates, Bahrain and Egypt had announced in the early hours of Monday they were pushing back a deadline for Qatar to agree to a list of 13 demands they issued on June 22.

A joint statement said they were extending the ultimatum, which had been due to expire at the end of the day on Sunday, at the request of Kuwait’s emir.

The demands included Doha ending support for the Muslim Brotherhood, closing broadcaster Al-Jazeera, downgrading diplomatic ties with Iran and shutting down a Turkish military base in the emirate.

Sheikh Mohammed had earlier said the list of demands was “made to be rejected.”

Saudi Arabia and its allies announced on June 5 they were severing ties with their Gulf neighbor, sparking the worst diplomatic crisis to hit the region in decades.

They accused Qatar of supporting extremism and of being too close to Saudi Arabia’s regional arch-rival Iran, which Doha has strongly denied.

The crisis has raised concerns of growing instability in the region, home to some of the world’s largest energy exporters and several key Western allies who host US military bases.

German Foreign Minister Sigmar Gabriel, who on Monday starts a tour of several Gulf states, called for “serious dialogue” to end the crisis.

“We are worried that the distrust and the disunity could weaken all the parties concerned as well as the entire peninsula,” said Gabriel, who will visit Saudi Arabia, the United Arab Emirates and Qatar.