Videos from inside the Shayrat air base showed fighter jets and hangars destroyed and runways pocked with holes after the strike in the pre-dawn hours Friday.
Saudi Arabia is one of the most vehement opponents of Assad.
Assad said the USA missile strikes on a Syrian air base, launched in response to the chemical weapons attack, only made him more determined. He also said the top US priority in the region hasn't changed and remained the defeat of Islamic State militants. "They can still commit massacres at any time", Abdulrzzak Khattab, a resident who said his house was damaged in Saturday's attack, told the Post.
The Kremlin maintained only 23 of the 59 cruise missiles reached the base, leaving the runways intact.
The U.S. missiles struck early Friday morning in Syria, targeting the Shayrat's airstrips, hangars, control tower and ammunition areas. The officials all spoke on the condition of anonymity to discuss internal deliberations and intelligence matters.
The U.S. says the strike was in response to a nerve gas attack on the rebel-held town of Khan Sheikhoun last week, which has been widely blamed on government forces.
Col. Hassan Hamade, a Syrian pilot who defected in June 2012 when he landed his MiG-21 in Jordan, agreed. He said that for that "this oppressive Assad needs to go". There are 25 air bases in Syria, including 20 under government control.
Tillerson said on CBS' "Face the Nation" that Russians were not targeted by the strikes. But she's also upset over yet more destruction.More news: Pearl Jam inducted to Hall of Fame
"We are asking for an impartial global fact-finding body to be set up.to find out where these chemical weapons came from", Iran's Rouhani said in a speech on Saturday.
"I discussed these plans in detail with Secretary Tillerson", Johnson said, adding that the United States foreign minister would still visit Moscow as planned following the G7 meeting to "deliver that clear and co-ordinated message to the Russians".
Assad's office called the strike "foolish and irresponsible", and Moscow announced a series of retaliatory steps including plans to strengthen Syrian air defenses.
Tillerson was a prominent fixture during the most important foreign policy period in Trump's young presidency: a two-day summit with Chinese President Xi Jinping that coincided with the strikes against Syria.
McMaster said Russian leaders were supporting "a murderous regime" and their actions would dictate the future of U.S.
"People are anxious that [the attack is] just to make some media noise", he said, "that this was a one-time US strike on the Shayrat airport, that they won't strike again, and the reckoning has ended".
"The United States failed to achieve its goal with this aggression, which was to raise the morale of the terrorist groups it supports after the victories achieved by the Syrian army", Assad told Rouhani, according to Syrian state news agency SANA. The strike that killed the woman happened in a residential neighborhood, activist Alaa Al-Youssef told CNN.
"Sources confirmed. that the regime and its allied forces have worked to re-repair the runway quickly, in order for these warplanes to take-off of it" the London-based Syrian Observatory reported.