Russia has denied its planes had conducted air strikes overnight against the Syrian rebel-held city of Idlib, which the Syrian Observatory for Human Rights said had killed 23 people.
"Russian planes did not carry out any combat missions, to say nothing of any air strikes, in the province of Idlib," Russian Defense Ministry spokesman Igor Konashenkov said in a statement on May 31.
The observatory had earlier said the air strikes targeted a number of positions in the city, one of them next to a hospital. Seven children were among the dead, observatory head Rami Abdulrahman said.
The Turkish Foreign Ministry said the strikes had killed more than 60 civilians and complained in a statement about what it said were the "indefensible" crimes of the Russian and Syrian governments.
Konashenkov called the observatory's allegations "a horror story" and said such pronouncements should be regarded with greater skepticism.
Idlib is a stronghold of rebel groups including the Al-Qaeda-linked Al-Nusra Front.
The Russian Air Force deployed to Syria last year to support President Bashar al-Assad in the war with rebels seeking to end his rule.