The Trump administration is sending top national security officials to brief Congress on escalating tensions with Iran, agreeing to multiple meetings intended to head off growing frustration with the president and his senior advisers.

Daniel Coats, the director of national intelligence, and Gen. Paul Nakasone, who heads the National Security Agency and U.S. Cyber Command, met privately Thursday with the Gang of Eight, which includes the top Republicans and Democrats in the Senate and House and the heads of each chamber’s intelligence committee.

That session will be followed on Tuesday with separate briefings for all members of the House and Senate from Secretary of State Mike Pompeo, acting defense secretary Patrick Shanahan and Chairman of the Joint Chiefs of Staff Joseph F. Dunford Jr., according to aides apprised of those plans.

In each meeting, officials are expected to field questions about purported threats facing U.S. troops in the Middle East and the corresponding response from Washington, including the deployment of additional warplanes and a carrier strike group to the Persian Gulf, the decision to extract diplomatic personnel from Iraq, and reports of a possibly drastic expansion of the military’s footprint throughout the region.

Lawmakers in both political parties want clarity on the intelligence that has informed those measures, and many have become aggravated with the lack of information from the administration.

Across Congress, Democrats complain that the administration has stymied their efforts to obtain committee-level and individualized briefings regarding the crisis with Iran, negotiations with North Korea, military operations along the U.S.-Mexico border and the prospect of an intervention in Venezuela. Direct appeals for information have been rebuffed, diverted or unsatisfactorily addressed, leading Democratic members say, heightening the risk that the administration creates a global crisis before Congress is even aware of what has led to it.

“We don’t need another Iraq, weapons-of-mass-destruction moment,” Sen. Robert Menendez (N.J.), the Senate Foreign Relations Committee’s ranking Democrat, told reporters this week, alluding to the George W. Bush administration’s ultimately flawed justification for its 2003 invasion. “I’m alarmed that we cannot even get the basic briefings in a timely way.”

Some Republican leaders, including Senate Foreign Relations Committee Chairman James E. Risch (R-Idaho), have played down such complaints. Risch has stated repeatedly over the past two weeks that he is in continuous contact with the administration. Other Republicans, however, say the dearth of information is a concern.

“I think all of us are in the dark over here,” Sen. Lindsey O. Graham (R-S.C.), a member of the Senate Foreign Relations Committee, said this week.

Information from the White House is slow to reach Congress because President Trump and his advisers are often at odds over the best course of action, according to administration officials who, like others, spoke on the condition of anonymity to discuss the strained relationship.

The internal division spilled into public view Thursday, when Trump seemed to step in front of national security adviser John Bolton’s warnings of a potential military conflict with Iran. The president told reporters, “I hope not” when asked whether war was imminent.

The gap between Trump and his advisers means that even the most senior members of his administration are hard-pressed to communicate detailed plans to Congress — leading to bland briefings that irritate lawmakers by informing them only of what they already know, according to both Republicans and Democrats on Capitol Hill.

The House Intelligence Committee chairman, Rep. Adam B. Schiff (D-Calif.), said Thursday that although some administration briefings are substantive, “sometimes, there have been occasions where they have been so watered down as to be less informative than watching TV.” He noted that committee hearings have also been canceled at the White House’s request, or relegated only to the Gang of Eight — whose members are prevented from sharing with other lawmakers the classified information they receive.

This limits important information from reaching Congress and the public, Schiff said.

Thursday’s meeting with the Gang of Eight came after the administration abruptly canceled an Iran briefing for the House Intelligence Committee that had been scheduled for Wednesday, according to four people familiar with the matter.

House Democrats have faced steeper hurdles in seeking to obtain classified information about North Korea’s nuclear ambitions. Members of the House Intelligence Committee have complained that intelligence on the hermit kingdom has been “constricted.” The House Foreign Affairs Committee has sought a classified briefing on North Korea for at least four months, according to Democratic aides, and the committee has been told that attempts to schedule such a session are being resisted by senior White House officials, including Bolton.

The White House did not respond to a request for comment.

In justifying their decisions to not provide Congress with sensitive briefings, administration officials have cited concerns that lawmakers may disclose the information to the media. In March, for instance, when Pompeo was asked during a public hearing why lawmakers were unable to secure a briefing on the status of Afghanistan peace talks, he said that “the success of those negotiations depends on every one of those partners having confidence that what they say will not end up in The Washington Post.”

An aide on the House Foreign Affairs Committee said that this has prevented the panel from receiving updates about the administration’s plans for China and the Indo-Pacific region.

Yet several Democrats described a pattern by which the department and agency officials normally tasked to confer with lawmakers on such matters instead defer to the National Security Council for approval, which in turn quashes their requests to provide information to lawmakers.

Administration officials also complain of internal struggles with the NSC, which they say is attempting to keep tight control over the flow of information made public as the Iran standoff unfolds.

Garrett Marquis, the chief spokesman for the NSC, has told aides at other agencies to not comment publicly or release any statements to the media without explicit permission, frustrating staffers at the State Department and the Defense Department, officials said. The NSC also is attempting to keep a tight hold on information that goes to Congress, aides said.

Marquis declined to comment, as did representatives for the Pentagon and the State Department.

John Hudson contributed to this report.