Defense Secretary James Mattis is pushing back against President Trump’s calls for a larger military response to the recent chemical weapons strike in Syria, The Wall Street Journal reported Friday.

Citing unnamed U.S. and defense officials, the Journal said the military had scheduled two potential windows for the strikes, including one Thursday night, but Mattis canceled them both. The Pentagon chief is reportedly concerned that anything other than a “show strike” risks broader escalation in the region, particularly with the Russians.

The Journal reports Trump is dissatisfied with the limited options his advisers have presented. 

“He wants Mattis to push the limits a little bit more,” one White House official said.

The Trump administration is weighing military action after last weekend’s chemical weapons attack that the White House said Friday it has “high confidence” was carried out by the Syrian regime.

{mosads}Horrific images emerged of the dozens killed and hundreds injured in the attack in the Damascus suburb of Douma.

On Wednesday, Trump appeared to indicate a U.S. strike was imminent in a tweet taunting Russia.

“Russia vows to shoot down any and all missiles fired at Syria. Get ready Russia, because they will be coming, nice and new and ‘smart!’ You shouldn’t be partners with a Gas Killing Animal who kills his people and enjoys it!” Trump tweeted.

Hours later, however, Mattis pumped the brakes, saying the United States was still assessing whether the Syrian regime was behind the attack and working on options to respond.

“We’re still assessing the intelligence, ourselves and our allies. We’re still working on this,” Mattis told reporters at the Pentagon prior to meeting with defense officials from the Netherlands.

On Thursday, Mattis likewise told the House Armed Services Committee that no decision had been made on what action to take.

In the same hearing, Mattis also alluded to his concerns about the consequences of a strike.

“We’re trying to stop the murder of innocent people, but, on a strategic level, it’s how do we keep this from escalating out of control, if you get my drift on that,” he said.

Mattis worries that the administration lacks a broader strategy in the region, the Journal reported, and that a powerful retaliation could trigger a dangerous clash with Iran or Russia.