Iran's Revolutionary Guards warned they would strike U.S. facilities across the Middle East should any of their tankers face assault, according to Iranian outlets on Saturday, even as Washington awaited Tehran's reaction to its newest diplomatic overture.

The Guards declared that "any assault on Iranian tankers or commercial ships will trigger a severe response against an American outpost in the area and adversarial vessels," following U.S. actions against two Iranian tankers in the Gulf of Oman the previous day.

The UK's Maritime Trade Operations center reported early Sunday that a vessel had ignited after impact from an unidentified object near Qatar's shoreline.

A minor blaze erupted on the bulk carrier but was quickly contained, occurring 23 nautical miles - about 43 kilometers - northeast of Doha, Qatar's capital, per UKMTO.

President Donald Trump stated Friday he anticipated Iran's response to the U.S. peace proposal "supposedly tonight."

Although Tehran may have relayed a reply through Pakistani intermediaries, no official confirmation emerged, and Foreign Minister Abbas Araghchi cast doubt on U.S. credibility.

"Recent U.S. military escalations in the Persian Gulf, including repeated ceasefire breaches, have heightened doubts regarding America's true intent and commitment to diplomacy," Araghchi remarked during a discussion with his Turkish counterpart, as covered by Iran's ISNA news service.

The prior day, a U.S. warplane targeted and neutralized two tankers flying Iran's flag, which Washington claimed defied its port blockade; an Iranian officer informed domestic media that their navy retaliated with counterstrikes.

This incident capped escalating clashes in the Strait of Hormuz, a crucial global shipping artery Iran aims to dominate for toll collection and leverage against the U.S. and allies.

Washington deems Tehran's bid to control this vital oil corridor intolerable.

Through Pakistani channels, the U.S. forwarded Iran a plan to prolong the Gulf truce, paving the way for negotiations on resolving the 10-week conflict sparked by U.S.-Israeli operations against Iran.

French network LCI correspondent Margot Haddad noted Saturday that Trump, in a quick exchange, affirmed he expected Iran's position "very soon."

Iran's foreign ministry spokesman indicated Friday the offer remained "under consideration."

Secretary of State Marco Rubio conferred Saturday with Qatar's leader, a pivotal U.S. conduit to Iran, on "sustained collaboration to counter dangers and foster stability throughout the Middle East," per the State Department.

Qatar's Sheikh Mohammed bin Abdulrahman Al Thani had met U.S. Vice President JD Vance the day before to address Pakistan-facilitated pushes for lasting peace.

Iran has struck Qatari locations amid the conflict, citing the Gulf state's hosting of a prominent U.S. airbase.

Oil Slick Detected Near Kharg Island

Satellite footage meanwhile revealed a suspected oil spill expanding off Iran's Kharg Island, a cornerstone of its petroleum exports.

The source of the spill, visible along the island's western shore and spanning over 20 square miles - roughly 52 square kilometers - remained unclear, as reported by monitor Orbital EOS.

The Conflict and Environment Observatory, a UK nongovernmental group, informed AFP that the slick had significantly diminished by Saturday, possibly stemming from damaged oil facilities.

Central to Iran's export operations and economy, Kharg Island sits deep in the Gulf, well north of the constricted Strait of Hormuz.

Since hostilities began February 28, Iran has mostly sealed the strait, roiling world markets and spiking crude prices.

The U.S. countered with a blockade of Iranian harbors, though Trump recently halted a brief naval push to restore commercial passage through the strait.

Clashes Intensify on Lebanon Border

A companion truce along the Lebanon front teeters as Israel and Iran-supported Hezbollah trade fire daily.

Lebanese officials reported at least nine fatalities from Israeli airstrikes in the south Saturday, with state outlets detailing raids on a road south of Beirut beyond Hezbollah's core areas.

These barrages marked some of the fiercest since a three-week-old ceasefire took hold between Israel and Hezbollah.

Hezbollah claimed drone strikes on Israeli forces in the north at least twice, retaliating against ongoing attacks.

Israel's armed forces confirmed multiple explosive drones entering its airspace, injuring one reservist gravely and two others seriously.

The renewed violence precedes direct Lebanon-Israel talks in Washington next week - a development Hezbollah fiercely rejects - amid their formal war since 1948.