As President Donald Trump considered US options in Syria, Defense Secretary Jim Mattis on Monday took aim at Russia for what he suggested was its failure to ensure the elimination of Syria's chemical weapons arsenal. The Pentagon chief said he would not rule out a US military strike against Syria in response to a suspected poison gas.
Trump planned two meetings with senior national security aides on Syria, in addition to a previously scheduled late-afternoon White House conference with leaders of US military commands around the world. Monday was the first day on the job for Trump's new national security adviser, John Bolton, who has previously advocated military action against Syria.
The White House deliberations came as Russia and the Syrian military blamed Israel for a pre-dawn missile attack on a major air base in central Syria, saying Israeli fighter jets launched the missiles from Lebanon's air space. A group that monitors Syria's civil war said the airstrikes killed 14 people, including Iranians active in Syria.
Over the weekend Trump threatened a "big price to pay" for the suspected poison gas attack Saturday in Syria that killed at least 40 people, including children. The government of President Bashar Assad has denied using poison gas.
Officials in Washington were seeking to verify early reports by rescuers and others that the Assad government was culpable. The Russian military, which has a presence in Syria as a key Assad ally, said its officers have visited the site of the attack in the suburbs of Damascus, the Syrian capital, and found no evidence to back up reports of poison gas being used.
At a photo-taking session in the Pentagon on Monday, Mattis said "the first thing" to consider in how to respond to the attack is why chemical weapons are "still being used at all." He noted that Russia was a guarantor of a 2013 agreement to eliminate Syria's entire chemical weapons arsenal, suggesting Moscow shares blame for the suspected gas attack.
"And so, working with our allies and our partners from NATO to Qatar and elsewhere, we are going to address this issue," Mattis said in brief remarks to reporters as he began a meeting with the emir of Qatar.
Asked whether he ruled out launching retaliatory US airstrikes in Syria, Mattis said, "I don't rule out anything right now."
The US military has a wide range of warplanes and other capabilities in the Middle East that could carry an attack. They include sea-launched cruise missile aboard ships within range of Syria.
Syria's state news agency SANA initially said the attack on the T4 air base was likely "an American aggression," but Pentagon spokesman Christopher Sherwood quickly denied the United States was behind the strike and the agency then dropped the accusation, blaming Israel instead.
Saturday's suspected poison gas attack took place in a rebel-held town near Damascus amid a resumed offensive by Syrian government forces after the collapse of a truce. Syrian activists, rescuers and medics said the attack in Douma killed at least 40 people, with families found suffocated in their houses and shelters. The reports could not immediately be independently verified.
As US officials consider whether and how to respond, they are looking at what type of chemical agent was used. When Trump ordered airstrikes last year after a chemical weapons attack, it was a response to the use of Sarin gas, which is banned by the Chemical Weapons Convention that Syria has signed.
An attack with chlorine, which can be used as a weapon but is not outright banned by the treaty, could raise precedent issues, as there have been numerous recent allegations of chlorine attacks in Syria that have drawn no response from the Trump administration.
One year ago this month, Trump ordered dozens of cruise missiles to be fired at a Syrian air base after declaring there was no doubt Assad had "choked out the lives of helpless" civilians in an attack that used banned gases. White House advisers said at the time that images of hurt children helped spur the president to launch that air strike, and television new shows on Sunday aired similar depictions of suffering young Syrians.
On Sunday, Trump tweeted: "Many dead, including women and children, in mindless CHEMICAL attack in Syria. Area of atrocity is in lockdown and encircled by Syrian Army, making it completely inaccessible to outside world. President Putin, Russia and Iran are responsible for backing Animal Assad. Big price to pay. Open area immediately for medical help and verification. Another humanitarian disaster for no reason whatsoever. SICK!"
Republican Sen. John McCain of Arizona said Assad heard Trump's signal that he wanted to withdraw from Syria and, "emboldened by American inaction," launched the attack. In a statement, McCain said Trump "responded decisively" last year with the air strike and urged Trump to be forceful again to "demonstrate that Assad will pay a price for his war crimes."
Trump's homeland security adviser, Thomas Bossert, noted on ABC's "This Week" the timing of the suspected chemical attack - almost a year to the day of the US missile strikes.
Asked about the potential for an American missile strike in response, Bossert said: "I wouldn't take anything off the table. These are horrible photos. We're looking into the attack at this point."