A senior administration official said Friday that the intelligence showed that Mr. Suleimani was planning to have forces carry out some sort of attack in the region that would result in mass casualties of Americans, with the intent of getting the American military to withdraw from Iraq, one of his main missions. But the official provided no further details.

Some Pentagon and State Department officials have said since the killing of General Suleimani that there was nothing in intelligence that showed threats that were out of the ordinary. They said the United States was aware that General Suleimani was always capable of lethal attacks on Americans and at any given time would have various plans underway.

Administration officials say General Suleimani and the Quds Force, which is an arm of the Islamic Revolutionary Guards Corps, are responsible for the deaths of hundreds of Americans, most of them soldiers who were fighting in Iraq in the mid-2000s. At the time, the Quds Force passed technology and training to Iraqi Shiite militias that allowed the militias to make powerful explosives that could penetrate armored vehicles used by the American military. They were the deadliest types of roadside bombs encountered by Americans in the war.

Last April, the Trump administration designated as a terrorist organization the Revolutionary Guards, a wing of the Iranian military. It was the first time the United States had used that label against a part of another government.

On Friday, Mr. Pompeo and the Treasury secretary, Steven Mnuchin, announced new sanctions on Iranian officials and on a few companies — including two in China — involved in the production and export of Iranian steel and other metals. The Trump administration had already imposed major sanctions on Iran’s metals industry after Mr. Trump’s withdrawal in 2018 from a landmark nuclear agreement with the country, so analysts said the new sanctions would have little additional effect.

The damage to Iran from the new sanctions will be negligible, said Peter Harrell, a sanctions expert at the Center for a New American Security in Washington. “When it comes to putting materially more economic pressure on Iran, the Trump administration is something of a victim of its own success — and I think we are reaching the end of the road for what ‘maximum pressure’ can achieve when it comes to Iran’s economy,” Mr. Harrell said.

The successful drone strike against General Suleimani on Jan. 3 at Baghdad International Airport, which Iraqi officials say killed five Iranians and five Iraqis in a two-car convoy, and the unsuccessful attack in Yemen appeared aimed at knocking the Islamic Revolutionary Guards Corps back on its heels. Some senior military and intelligence officials had argued internally that significant strikes against the group would effectively damage Iran’s ability to direct its proxy forces.