"We strongly condemn hideous air attack led by US coalition on #Idlib #RedCrescent HQ. It's clear #warcrime and #IHL violation," Kinik wrote on Twitter.
Idlib's medical facilities have previously been targeted by strikes, with a maternity hospital suffering shelling and a hospital supported by the Doctors Without Borders (MSF) destroyed last summer.
Syria has been in a state of civil war since 2011, with government forces fighting the Syrian opposition and terrorist groups. The Idlib province is still predominantly in the hands of Jabhat Fatah al Sham, formerly known as the Nusra Front, outlawed in Russia.