WASHINGTON — Osama Siblani was sipping his morning coffee at the office when his phone buzzed with a message from one of President Joe Biden’s advisers. As publisher of the Arab American News in Dearborn, Michigan, Siblani serves as an occasional sounding board, and the White House wanted to know what he thought of Biden’s recent call with Israeli Prime Minister Benjamin Netanyahu.

After months of mounting concerns over the suffering of Palestinians in Gaza, Biden had publicly, albeit vaguely, threatened to cut U.S. assistance to Israel’s military operations in the Hamas-controlled territory.

“This is baby steps,” Siblani said he responded. “What we need is giant steps rather than baby steps.”

The text exchange is an example of the behind-the-scenes communication that the White House has nurtured at a time of anger at the Democratic president over his support for Israel. Such informal contacts have become more important as some Muslim and Arab American leaders have turned down opportunities to talk with Biden or his advisers, frustrated by the sense their private conversations and public anguish have done little or nothing to persuade him to change course.

The White House says it is keeping an open door for difficult conversations, but it can be hard to get people to walk through.

“All they are trying to do is convince us that there is some kind of movement toward where we want,” Siblani said. “But it’s too slow and it’s dragging. It’s more death and casualties that are happening.”

The highest-profile example of the stonewalling came last week when a Palestinian American doctor walked out of a meeting with Biden. But interviews with Muslim and Arab American leaders reveal how that face-to-face protest was only the most conspicuous case of a fracture that has damaged crucial relationships and closed avenues needed to repair them.

“What more can we tell the White House for them to change course? I’ve run out of words,” said Michigan state Rep. Abraham Aiyash, who met with senior officials in February but has not had any contact with them since then.

Dan Koh, deputy director of the White House Office of Intergovernmental Affairs, said the administration wants “to make sure we’re as accessible as possible.”

“We understand that some people do not want to engage. We respect that,” he said. “But we think that the people who have engaged have felt that it was a fruitful discussion.”

Top White House officials, including national security adviser Jake Sullivan, senior adviser Anita Dunn and chief of staff Jeff Zients, have been involved in the outreach. Biden is briefed on their conversations, and Vice President Kamala Harris has talked with Muslims, Arab Americans and Palestinian Americans.

The White House believes it still can find receptive audiences, such as a recent series of meetings with Lebanese Americans that focused on efforts to prevent the conflict from expanding along Israel’s northern border, where Hezbollah operates.

But the situation presents a challenge for a president who believes in the political power of personal relationships and has prized his history of sitting down with opponents and critics. It could also jeopardize his reelection this year, with some Muslims warning they are unwilling to support Biden even it that risks returning Donald Trump, the presumptive Republican nominee, to the White House.

Salam Al-Marayati, who lives in Los Angeles and leads the Muslim Public Affairs Council, described the attitude as, “Forget them. They have to learn a lesson. And if they lose, that’s the lesson they should learn.”

His disillusionment with Biden began soon after the war started on Oct. 7, when Hamas killed 1,200 Israelis in a surprise attack. The president described himself as a Zionist during a trip to Israel later that month, emphasizing his belief in the importance of a Jewish state as a guarantee of security for people who have historically been persecuted around the world.