Qatar says tightening Iran sanctions harm oil-consuming nations.

The foreign minister of Qatar said on Wednesday that Washington’s decision not to extend sanction waivers on Iranian oil exports would harm countries that rely on the supplies.

The United States has demanded that buyers of Iranian oil stop purchases by May 1 or face the prospect of sanctions, ending six months of waivers that had allowed Iran’s eight biggest customers, most of them in Asia, to import limited volumes.

“The sanctions should not be extended because they have an adverse impact on countries benefiting from Iranian oil,” Sheikh Mohammed bin Abdulrahman al-Thani told a press conference in Doha.

“In Qatar, we do not believe unilateral sanctions bring positive effects for crises which must be solved through dialogue and dialogue only,” he added.

Oil markets have tightened this year due to supply cuts led by the Organization of the Petroleum Exporting Countries (OPEC). The White House said after its Iran move that it was working with Saudi Arabia and the United Arab Emirates to ensure oil markets were “adequately supplied”.

Qatar, one of OPEC’s smallest oil producers, in December, quit the exporting group to focus on maintaining its position as the world’s top liquefied natural gas exporter, a move seen as a swipe at OPEC’s de facto leader, Saudi Arabia.

Saudi Arabia, the UAE, Bahrain, and Egypt cut diplomatic and trade ties with Qatar in June 2017, accusing it of supporting terrorism and their regional foe Iran. Doha denies the charges and says the boycott aims to impinge on its sovereignty.

Sheikh Mohammed said there was no sign of a thaw in the row.

“Unfortunately, we still see the same behavior of the blockading states of stubbornness and denial. We hope that one day they will go back to the wisdom and will come back to the table and address the grievances in front of us,” he said.

In November, the minister said Doha would continue to deal with Iran, which helped Qatar to secure supplies when the boycott was first imposed, and that it was ready to mediate between Washington and Tehran.