The New York Times
WASHINGTON — President Trump has drawn a new red line for President Bashar al-Assad of Syria, with American officials describing preparations at a Syrian air base for a chemical weapons assault as they sought Tuesday to bolster Mr. Trump’s threat to deter an attack.
But the administration elaborated little on the president’s unexpected, 87-word statement a night earlier that warned that Mr. Assad would “pay a heavy price” if he again released toxic gas on rebel-held territory, leaving lingering questions in Washington and in the Middle East about Mr. Trump’s intentions in Syria.
American officials have declined to rate their level of confidence about whether a chemical attack is imminent or to say whether the administration has pursued diplomatic channels to stop it. Military officials, who were initially caught off guard by Monday night’s White House statement, would not discuss what options they were considering. Conversations with allies about the chemical weapons intelligence have been kept largely secret.
In previous administrations, debates about how best to deter atrocities have played out publicly around the world. President George W. Bush took months to argue his case — later proved to be flawed — about the existence of weapons of mass destruction in Iraq. President Barack Obama offered detailed explanations about his deliberations on how to respond when Mr. Assad used chemical weapons to kill 1,400 people in 2013.
On Tuesday, White House officials said only that Mr. Trump’s statement spoke for itself.
That silence added to the uncertainty about whether a new military confrontation with Syria was looming just two months after Mr. Trump fired dozens of Tomahawk missiles at a Syrian base, Al Shayrat airfield, after a chemical weapons attack that killed dozens.
Mr. Assad’s government vigorously denied the accusation of preparations for an attack, calling Mr. Trump’s statement a provocation. And in Russia, a close ally of Syria’s, a senior lawmaker accused the United States of using the declaration about chemical weapons to plan an attack on Syria.
As if to punctuate his contempt for the Trump administration’s warning, Mr. Assad visited a Russian air base near Latakia in the western part of the country on Tuesday, accompanied by Gen. Valery V. Gerasimov, the Russian military’s chief of staff. The Syrian news media, which reported the visit, distributed a video clip of Mr. Assad climbing into the cockpit of a Russian Sukhoi Su-35 parked at the base, where Russia has conducted many of its bombing operations to support the government’s side in the six-year civil war.
In Washington on Tuesday, American officials explained only briefly what had prompted the White House effort at deterrence. Capt. Jeff Davis, a Pentagon spokesman, told reporters that what looked like active preparations for a chemical attack had been seen at Al Shayrat. One Pentagon official said an aircraft shelter at the base that had been hit by an American Tomahawk missile in April was being used for the preparation.
Monday’s statement caught military officials by surprise, with one at the United States Central Command, which oversees combat operations in the Middle East, saying at the time that he had “no idea” what it was referring to.
The highly classified nature of the intelligence — and the likelihood that it involved information provided by an American ally — kept the assessment and the potential administration response closely held, two American officials said.
A White House spokeswoman, Sarah Huckabee Sanders, said on Tuesday that relevant agencies, including the Pentagon, the State Department, the C.I.A. and the Office of the Director of National Intelligence, had been involved in issuing the statement. But White House officials repeatedly declined to provide details about the timing or content of the deliberations.
“Not going to comment further,” Sean Spicer, the White House press secretary, said in response to several emailed questions.
An American defense official said that Defense Secretary Jim Mattis had been aware of the movements at Al Shayrat and that the White House statement was coming.
Secretary of State Rex W. Tillerson “was aware of” the White House statement and had informed his Russian counterpart, Foreign Minister Sergey V. Lavrov, on Monday morning about the American concerns, said Heather Nauert, a State Department spokeswoman. But she said she could not share evidence of the Syrian preparations because it was “an intelligence matter.”
Representative Adam B. Schiff of California, the ranking Democrat on the House Intelligence Committee, said the administration had briefed him before the White House issued its statement. But he declined to comment on what had caused the concern that Syria might be readying a chemical strike.
“If further use of chemical weapons can be discouraged, I think that’s worthwhile,” Mr. Schiff said in a telephone interview.
Neither White House nor Pentagon officials said an attack, or retaliation, was imminent in Syria, where the United States is backing Syrian fighters combating Islamic State militants on an increasingly complex battlefield.
“The Department of Defense remains focused on operations to defeat ISIS,” Maj. Adrian Rankine-Galloway, a Defense Department spokesman, said in a statement, using an acronym for the Islamic State. “Nevertheless, the continued brutality of the Assad regime and his use of chemical weapons presents a clear threat to regional stability and security, as well as the national security interests of the United States and our allies.”
The United States has closely monitored the Syrian air base since the Pentagon carried out the cruise missile strikes in April, using a combination of satellite imagery, electronic signals intercepts and on-the-ground spying.
In recent days, American and allied intelligence agencies detected activities at the base that were consistent with how the Syrian military prepared for using chemical weapons in the past, including preparation of aircraft and munitions. French officials said that during a telephone conversation Tuesday, Mr. Trump talked with President Emmanuel Macron about the need to work toward “a common response” to any chemical attack in Syria.
In Damascus, Ali Haidar, the Syrian minister for national reconciliation, was quoted by The Associated Press as saying that the government did not have chemical weapons. He accused the White House of releasing the statement to pave the way for a “diplomatic battle” against Syria at the United Nations.
Officials in Russia called the accusations “unacceptable.”
“I am not aware of any information about a threat that chemical weapons could be used,” Dmitri S. Peskov, the Kremlin spokesman, said on Tuesday.
Foreign Minister Mohammad Javad Zarif of Iran, Mr. Assad’s only regional ally, also rejected the Trump administration’s warning, describing it as a ploy.
“Another dangerous U.S. escalation in Syria on fake pretext will only serve ISIS, precisely when it’s being wiped out by Iraqi & Syrian people,” Mr. Zarif tweeted.
Mr. Trump has taken a different approach to the use of chemical weapons in Syria than Mr. Obama did. After the 2013 attack, Mr. Obama declined to strike the Syrian government, despite having declared the use of chemical weapons a “red line.” Instead, he agreed to a deal, proposed by Russia, for the government to dispose of its chemical weapons stockpiles and manufacturing capabilities.
But American officials suspect that Syria kept some of its means to produce chemical weapons.
“What’s driving this is that Assad is so short of manpower that when he goes on the offensive out east, he’s tempted to use chemical weapons and other strategic weapons elsewhere to prevent territorial loss,” said Andrew J. Tabler, a Syria analyst with the Washington Institute for Near East Policy.