Representatives from more than 60 countries met in Bahrain on Monday to discuss maritime security following attacks on tankers in the Gulf and Saudi oil installations.
The United States, other Western states and Saudi Arabia blame the attacks on Tehran, which denies any involvement.
"We all must take a collective stand... to take the necessary steps to protect our nations from rogue states," Bahraini Foreign Minister Khaled bin Ahmed Al-Khalifa told the meeting.
"This meeting comes at a critical moment in history," US Secretary of State Mike Pompeo wrote in a letter to the meeting's participants.
"The proliferation of weapons of mass destruction (WMD) and their means of delivery, whether by air or sea, poses a serious threat to international peace and security," he wrote.
"Together, we must all be committed to taking the necessary actions to stop countries that continue to pursue WMD at great risk to all of us," Pompeo said, in apparent reference to Iran.
Tension between Tehran and Washington has grown since the United States abandoned a multinational deal on curbing Iran's nuclear program last year and reimposed heavy sanctions on it.
The meeting's participants belong to the Maritime and Aviation Security Working Group, created in February during a Middle East conference in Warsaw.
"The meeting is an occasion to exchange views on how to deal with the Iranian menace and to guarantee freedom of navigation," Bahrain's foreign ministry said on Twitter.
Following recent attacks against tankers in the Gulf, the United States formed a naval coalition to protect navigation in a region that is critical to global oil supplies.
Bahrain, which hosts the US Navy's Fifth Fleet, joined the coalition in August. Saudi Arabia and the United Arab Emirates joined in September.
The United Kingdom and Australia are the principal Western partners of the US to have agreed to send warships to escort commercial shipping in the Gulf.
Most European states have declined to participate, fearful of undermining their efforts to save the nuclear accord with Iran, which was weakened by the US withdrawal.
Iran has presented its own regional plan to assure "energy security" and "freedom of navigation".