“The U.S. mission has not changed — the president has been clear that he wants U.S. forces to come home as quickly as possible,” Sarah Huckabee Sanders, the White House press secretary, said in a statement Sunday night. “We are determined to completely crush ISIS and create the conditions that will prevent its return. In addition, we expect our regional allies and partners to take greater responsibility both militarily and financially for securing the region.”
The new American sanctions were announced on Sunday by Nikki R. Haley, the ambassador to the United Nations and the administration’s leading public voice excoriating Russia in recent days. “They will go directly to any sort of companies that were dealing with equipment related to Assad and chemical weapons use,” she said on “Face the Nation” on CBS. “And so I think everyone is going to feel it at this point. I think everyone knows that we sent a strong message, and our hope is that they listen to it.”
Mr. Trump has tried through most of his presidency to forge a friendship with President Vladimir V. Putin of Russia and has largely avoided criticizing him personally even as a special counsel, Robert S. Mueller III, investigated whether Mr. Trump’s campaign coordinated with Russia during the 2016 election. But in recent weeks, his administration has taken increasing action against Russia, and the president singled out Mr. Putin over Syria’s use of chemical weapons on Twitter and again in a televised speech on Friday night.
New sanctions on Monday would be the third round enacted by the Trump administration against Russia in the past four weeks. Last month, the administration targeted Russian companies and individuals for intervening in the 2016 election and mounting cyberattacks against Western facilities. It followed that this month with penalties against Mr. Putin’s inner circle, singling out some of Russia’s richest men and top government officials.
The administration also expelled 60 Russian diplomats and intelligence officers and closed the Russian Consulate in Seattle in response to the poisoning of a former Russian spy living in Britain. Russia responded by expelling 60 American diplomats and closing the American Consulate in St. Petersburg.
Mr. Putin spoke with President Hassan Rouhani of Iran on Sunday to discuss the confrontation in Syria and reaffirm his opposition to the airstrike by American, British and French forces. “Vladimir Putin, in particular, stressed that if such actions, carried out in violation of the U.N. Charter, continue, it will inevitably lead to chaos in international relations,” the Kremlin said in a statement.
America’s allies in Britain and France declared that they were prepared to act again if necessary, but made clear that they did not want to become further involved in Syria. “The rest of the Syrian war must proceed as it will,” Boris Johnson, Britain’s foreign secretary, said on the BBC, adding that the “primary purpose is to say no to the use of barbaric chemical weapons.”
International inspectors from the Organization for the Prohibition of Chemical Weapons were in Syria on Sunday to start an investigation of the suspected chemical attack that killed dozens of people in the Damascus suburb of Douma on April 7 and prompted the American-led retaliatory strike. American officials have said video and other evidence points to the use of both chlorine and sarin gas by the Syrian government. Russia has asserted that the attack was fabricated to justify military action by the West.
The strikes against Syria were designed to avoid provoking Russia into a response. By hitting just three targets and limiting the attack to a single night, the Trump administration seemed to avoid compelling Moscow to lash back.
But Ms. Haley said the administration was determined to make Moscow pay a price for supporting Mr. Assad, noting that it had vetoed six United Nations resolutions related to Syria and chemical weapons.
“Assad knew that Russia had its back,” she said on “Fox News Sunday.” “Assad knew that Russia would cover for him at the United Nations, and Assad got reckless and he used it in a way that was far more aggressive.”
The White House did not respond to requests for comment on Sunday. The Treasury Department, which Ms. Haley said would issue the sanctions, declined to elaborate.
Mr. Trump sought on Sunday to defend his use of “mission accomplished” to characterize the Syria strike, a phrase that evoked memories of President George W. Bush’s visit to an aircraft carrier during the Iraq war that became a symbol of premature victory.
“The Syrian raid was so perfectly carried out, with such precision, that the only way the Fake News Media could demean was by my use of the term ‘Mission Accomplished,’” Mr. Trump wrote on Twitter. “I knew they would seize on this but felt it is such a great Military term, it should be brought back. Use often!”
Advisers said Mr. Trump meant only that the specific mission of hitting three targets in Syria had been carried out, not that the larger goal of thwarting Mr. Assad’s use of chemical weapons had been met. American officials have acknowledged that the strikes did not eliminate Syria’s chemical weapons capability but expressed confidence that they diminished them and hoped that they would deter Mr. Assad from using them again.
The phrase “mission accomplished” has been freighted since 2003 when Mr. Bush visited the aircraft carrier Abraham Lincoln after the fall of Saddam Hussein and declared the end of major combat operations in Iraq while appearing before a giant banner emblazoned with the words. Mr. Bush himself never used the phrase, and White House aides later said it was meant to congratulate the carrier crew as it returned home from a long mission, but it became a damaging symbol for Mr. Bush as the war raged on for years.
Critics said Mr. Trump was going too far in claiming success. “It is impossible to say at this point that the mission has been accomplished,” Senator Angus King, an independent from Maine, said on “State of the Union” on CNN. The operation was accomplished “with the precision that our military is capable of,” he added, “but saying that it has been a success, we won’t know until we see whether the regime continues to use chemical weapons.”
Other lawmakers focused on Mr. Trump’s decision to use force without consulting Congress, an issue that has flared under presidents of both parties for decades.
“President Trump is not a king,” Senator Tim Kaine, Democrat of Virginia, said on “Face the Nation.” “He’s a president. He’s supposed to come to Congress to seek permission to initiate a war. As Ambassador Haley said, they’ve been following these chemical weapons attacks for months. They clearly had time to come to Congress to seek our permission.”
Still, supporters of Mr. Trump and even some longtime detractors praised him for taking action against the use of chemical weapons without escalating so much that it might draw the United States deeper into Syria’s civil war or provoke a dangerous retaliation.
“I think this administration’s actions against Syria were appropriate,” John O. Brennan, who was C.I.A. director under President Barack Obama, said on “Meet the Press” on NBC. “And I tend to be a critic of this administration. But I think the way they handled this was exactly right.”