A possible US-backed thaw in Qatari-Saudi relations has been signalled by Qatar’s prime minister agreeing to attend a major summit in Mecca on alleged Iranian aggression in the region.

The attendance of Sheikh Abdullah bin Nasser bin Khalifa al-Thani at the summit, confirmed by Al Jazeera, the Qatari-owned news channel, on Wednesday, will be seen as the biggest sign of rapprochement between the two countries. The Saudis launched a sweeping economic and political blockade against the gas-rich country two years ago, accusing Doha of trying to undermine Saudi Arabia, fund terrorism and promote the Muslim Brotherhood across the Middle East.

King Salman bin Abdulaziz al-Saud, of Saudi Arabia, invited Qatar’s emir, Sheikh Tamim bin Hamad al-Thani, to attend the emergency Gulf cooperation council summit on Iran’s alleged role in attacking Gulf shipping and oil installations. Al Jazeera said Sheikh Abdullah would attend in his place, the first high-level contact between the two countries for more than two years.

The summit will be held on Thursday in Mecca. A Qatari plane carrying one of its diplomats was allowed to land in Saudi for the first time in two years on Monday.

Saudi airspace remains closed for all other Qatari flights, as it has been since the start of the boycott.

Qatar – unlike Saudi Arabia, Bahrain and the United Arab Emirates – has so far maintained its support for the Iran nuclear deal. Although determined to follow an independent foreign policy, it will not be seeking to alienate Donald Trump by spurning Washington’s pressure to curtail Iranian aggression in the region. Qatar has an economic interest in ensuring gas and oil installations are not the subject of attacks by Iranian proxy forces. It also acts as the host to the largest US military base in the Gulf.

Riyadh has accused Tehran of ordering the recent drone attacks on two oil-pumping stations in the kingdom, claimed by Yemen’s Houthis.

Iran denied it was behind the attacks and a succession of Iranian politicians have said they are not seeking a military confrontation, although they want crippling US economic sanctions to be lifted.

The Saudi-owned news outlet Arab News urged Washington to launch a surgical strike against Iran, but this view was not universally held across Saudi media.

Washington has blown hot and cold in its demands on Iran, with Trump saying he was not seeking regime change in Tehran, merely a renegotiation of the nuclear deal. He said the deal was full of loopholes that allowed Tehran to achieve nuclear breakout too rapidly.

Qatar is likely to urge caution on all sides, as well as privately appeal to Tehran not to sponsor proxies to attack Saudi oil assets. The Houthi rebel forces in Yemen, increasingly capable of mounting drone attacks, have the ability to operate independently from Iran.

Iran’s deputy foreign minister, Seyed Abbas Araghchi, has been trying to counter Saudi diplomacy by holding bilateral meetings in the region, including in Qatar, Kuwait and Oman.

The US has been putting private pressure on Saudi Arabia and Qatar to bury their differences ahead of the imminent publication of the Middle East peace plan by Trump’s son-in-law Jared Kushner. The “deal of the century”, due to be discussed at the economic workshop for Gulf finance ministers in Manama, Bahrain, in June, centres on a plan to help the Palestinian territories economically. Kushner is touring the region to promote the plan and to try to secure political buy-in. He is also due to join Trump on his state visit to the UK at the start of June.

Qatar has been one of the largest humanitarian funders of Gaza, and Doha’s buy-in for any economic reconstruction plan is highly prized by Washington.

But any suggestion a thaw in Saudi-Qatar relations will easily turn into a full-blown rapprochement seems unlikely. Marking the second anniversary of the start of the boycott, Qatar’s foreign minister recalled “the stabbing of the Qatari people in a premeditated crime of piracy, fabrication, and lies in which the appellant justified its unjust blockade against a country and its people”.