President Donald Trump has warned Syria's government the US is "locked and loaded" to strike again if it carries out new chemical attacks.
The warning came after the US, UK and France struck three Syrian sites in response to a suspected deadly chemical attack in the town of Douma a week ago.
Syria denies any chemical use and says that attack was fabricated by rebels.
A UN Security Council vote brought by Syria's ally, Russia, and condemning the US-led strikes was rejected.
The wave of strikes represents the most significant attack against President Bashar al-Assad's government by Western powers in seven years of Syria's civil war.
What has been the reaction to the strikes?
There was a bitter exchange at a UN Security Council emergency meeting on Saturday as Russia sought to secure a condemnation of the early morning air strikes by Western powers.
Ms Haley said the US and its allies had given diplomacy "chance after chance" but Russia had continued to veto UN resolutions.
Bashar Jaafari, Syria's envoy to the UN, said the US, UK and France were "liars, spoilers and hypocrites" who exploited the UN "to pursue your policy of interference and colonialism".
On the 15-member council only China and Bolivia voted in favour of Russia's resolution.
Other reaction included:
UK PM Theresa May said there was "no practicable alternative to the use of force" but also added the strikes were not about "regime change"
Turkish President Recep Tayyip Erdogan said the strikes were "appropriate" in retaliation for "inhumane" Syrian attacks
Israeli PM Benjamin Netanyahu expressed his "total support" for the air strikes
Iranian President Hassan Rouhani said the US was trying "to justify their presence in the region"
China said it opposed the use of force and that there could only be a political solution to the Syrian conflict.
What happens next?
The focus will be in Douma, and the visit by the OPCW inspectors. Syria said they were meeting officials in Damascus on Saturday evening and that a visit to the site of the alleged chemical attack was being facilitated.
The Syrian army also announced on Saturday that the Eastern Ghouta region, where Douma is situated, had been cleared of the last rebel fighters and was fully retaken.
There were also unconfirmed reports of a large blast south of Aleppo on Saturday evening and other attacks on Syrian forces near Deir al-Zour, suggesting areas of the Syrian conflict are far from over.