Latest: Russian military say they will help Syria strengthen air defences following US strike

Latest: Syrian President Bashar Assad's office has denounced the US strike, describing it as "reckless, irresponsible behaviour".

What we know so far:

• President Donald Trump ordered US air strikes on Syria;
• 59 Tomahawk missiles targeted Shayrat airfield near Homs;
• The action follows a suspected chemical attack on civilians in a rebel-held town;
• Trump said the attack was "in vital national security interest";
• Russia condemned US "aggression", has suspended a deal with the US and will help strengthen Syria's air defences.