People across the Middle East waited uneasily on Saturday for a decision from President Trump about a proposal to end the war with Iran, as the United States reaffirmed its resolve to emerge with a deal he finds acceptable.

Mr. Trump said on social media on Friday that he was meeting with advisers at the White House Situation Room to make a “final determination” about the proposed deal, but that meeting ended with no announcement.

Mr. Trump has zigzagged on his positions during the negotiations, vacillating between talk of progress on a deal and threats of renewed strikes.

Later on Friday evening, Iran said there was still “no final agreement” with the United States. Esmaeil Baghaei, the Iranian Foreign Ministry spokesman, told state television that while “message exchanges are of course ongoing,” a deal was not yet in hand.

Some people in Iran who had hoped that the war could lead to the end of the Islamic Republic’s authoritarian rule said they were disillusioned and indifferent to the idea of a potential agreement.

“We know that even if there is one, we will not receive any benefits from it,” said Ali, a 43-year-old engineer from Mazandaran Province in northern Iran, who asked to be identified only by his first name, fearing government retaliation.