The Trump administration appears divided on whether the U.S. is pursuing a policy of regime change in Syria, days after the first direct American military attack against the Syrian government.

Thursday’s strike “was related solely to the most recent horrific use of chemical weapons,” Secretary of State Rex Tillerson told ABC News’ George Stephanopoulos on Sunday. The goal of the attack was to send a message to Syrian President Bashar Assad and its ally Russia that the U.S. wouldn’t tolerate the use of chemical weapons, he continued. “Other than that, there is no change to our military posture.”

But United Nations Ambassador Nikki Haley said there can be no peace in Syria with Assad in power. “There’s not any sort of option where a political solution is going to happen with Assad at the head of the regime,” she told CNN’s Jake Tapper on Sunday. “Regime change is something that we think is going to happen because all of the parties are going to see that Assad is not the leader that needs to be taking place for Syria.​”​

Though Haley stopped short of indicating the U.S. would take military action to overthrow the Syrian dictator, her comments reflect a sharp change from the administration’s previous position. At the end of last month, Haley told reporters that the U.S. priority in Syria “is no longer to sit there and focus on getting Assad out.” At the same time, Tillerson said Assad’s fate would be decided by the Syrian people.

Days later, after a chemical weapons attack on Syrian civilians that the U.S. blames on Assad’s regime, the Trump administration sharpened its rhetoric and launched several dozen cruise missiles at a Syrian airfield, marking the first U.S. military effort against the Assad government.

President Donald Trump’s military attack on the Assad regime was, in itself, a stark reversal from his earlier position to work with Russia, Syria’s key ally, to negotiate a solution to the country’s civil war. He suggested on the campaign trail that Assad was an unsavory but stable ruler, and that the U.S. should not focus on pushing him out of power.

Now, the administration appears to be unsure of its policy. Tillerson on Sunday blamed Moscow for failing to prevent the Assad regime from using chemical weapons, despite a 2013 Russian-organized agreement in which the Syrian government was to surrender its chemical weapons arsenal.

White House National Security Adviser Lt. Gen. H.R. McMaster said in an interview with Fox News on Sunday that he hoped the chemical weapons attack would prompt Russia to reconsider its support for Assad. “Russia should ask themselves, ‘What are we doing here? Why are we supporting this murderous regime that is committing mass murder of its own population and using the most heinous weapons available?’” McMaster said.

The secretary of state is set to travel to Moscow later this week. He said he will remind his counterpart of Russia’s obligation to act as the guarantor of the agreement to eliminate chemical weapons from Syria.

“I don’t draw conclusions of complicity at all, but clearly they’ve been incompetent and perhaps they’ve just simply been out-maneuvered by the Syrians,” Tillerson said of Russia. “I hope Russia is thinking carefully about its continued alliance with Bashar al-Assad because every time one of these horrific attacks occurs, it draws Russia closer into some level of responsibility.”

This article has been updated to include McMaster’s comment.