Top US diplomat Marco Rubio arrived in Bahrain on Thursday, seeking to reassure Gulf allies that Washington will safeguard their interests as negotiations continue toward a final settlement to end the war with Iran.

Global oil markets reacted swiftly to the diplomatic push, with Brent crude dropping to its lowest level since the conflict began in February, a war that has severely disrupted energy supplies from the Middle East.

At the White House, President Donald Trump met NATO chief Mark Rutte on Wednesday, declaring that talks with Tehran were “going great.” He also requested nearly $88 billion in supplemental funding from Congress to cover mounting war costs, just a day after lawmakers demanded he seek explicit authorization for continued military action.

Rubio’s regional tour comes as Gulf states, battered by Iranian missile and drone strikes and facing a blockade of the Strait of Hormuz, press Washington to address their security concerns. Tehran, meanwhile, has portrayed the initial US-Iran deal—brokered with Pakistani mediation—as a declaration of “America’s defeat.”

In Kuwait City, Rubio pledged that Washington would remain “completely aligned” with Gulf partners during negotiations. He is scheduled to attend a Gulf Cooperation Council meeting in Bahrain after meeting leaders in Kuwait and the UAE.

The preliminary agreement set a 60-day window for talks but left unresolved Gulf nations’ concerns over Iran’s missile program and regional proxies. Rubio insisted the US would not compromise allies’ security.

Strait of Hormuz Dispute

Iran has vowed to retain control of the strategic waterway and impose maritime fees, a stance rejected by Washington and Gulf states, who demand toll-free navigation. Qatar’s prime minister has opened talks in Oman with Iraq, Iran, and Gulf countries to seek a compromise.

Lebanon Front

Iranian negotiator Mohammad Bagher Ghalibaf emphasized that peace in Lebanon—where Hezbollah’s attacks on Israel drew the country into the war—remains central to any final agreement. Violence has subsided, though tensions flared after an Israeli drone strike killed two people in southern Lebanon this week.

Separate reconciliation talks between Gulf states and Iran are expected in Saudi Arabia, though no date has been set.