Iran's foreign ministry on Tuesday accused the United States of violating a fragile ceasefire during the past 48 hours in the southern coastal province of Hormozgan, without specifying the incident.

"The U.S. terrorist army, continuing its illegal and unjustified actions since the ceasefire ... has, in the past 48 hours, committed a gross violation of the ceasefire in the Hormozgan region," the ministry said in a statement.

Iran's Islamic Revolutionary Guards said on Tuesday that they had downed a U.S. drone and shot at other aircraft entering the country's airspace.

U.S. military aircraft "entered Iranian airspace in the Persian Gulf region, and air defense units of the Islamic Revolutionary Guard Corps... identified and shot down an MQ-9 drone," the Guards said in a statement on their Sepah News website.

Iran's Supreme Leader Mojtaba Khamenei said on Tuesday that regional countries would no longer be shields for U.S. bases, in a written statement carried by state television.

"What is certain in this regard is that the hands of time will not turn backwards, and the nations and lands of the region will no longer serve as shields for American bases," said Khamenei, who has not appeared in public since he took office in March, in a message marking the Eid al-Adha holiday.

U.S. President Donald Trump said Monday that Saudi Arabia and other Muslim-majority nations must normalize ties with Israel as part of efforts to reach a deal with Iran, adding fresh uncertainty into protracted peace negotiations.

Iran warned Monday that, while some progress had been made, it was not yet close to striking a deal with the United States to end the Middle East war, after a weekend of mixed messages from Washington and Tehran.

World oil prices tumbled on renewed optimism about an agreement, after top U.S. diplomat Marco Rubio suggested a deal could be reached within the day -- but Iran's foreign ministry spokesman responded: "No one can make such a claim."

U.S. President Donald Trump has assured Israeli Prime Minister Benjamin Netanyahu he will hold firm on his demand for the dismantling of Iran's nuclear program as a condition in any final agreement with Tehran, a senior Israeli official told AFP on Sunday.

U.S. President Donald Trump said Sunday that he had told U.S. negotiators "not to rush into a deal" with Iran, amid anticipation that an agreement to end the war in the Middle East was close.

"The negotiations are proceeding in an orderly and constructive manner, and I have informed my representatives not to rush into a deal in that time is on our side," Trump wrote on his Truth Social account.

Pakistan's Prime Minister Shehbaz Sharif said on Sunday he hoped his country could soon host the next round of peace talks between Iran and the United States.

U.S. Secretary of State Marco Rubio said an announcement was possible later Sunday on a deal with Iran that could formally end the Middle East war, insisting goals had been met.

The United States and Iran could strike a deal to end the Middle East war as early as Sunday, Washington's top diplomat said, while Tehran insisted the agreement would do nothing to limit its nuclear program.