The Turkish health minister has said tests on victims of a chemical attack on a vilage in northern Syria show they had been exposed to Sarin, according to the Anadolu news agency.

The minister said tests on the victims had confirmed use of the nerve agent.

The report comes as G7 ministers rejected a call by Foreign Secretary Boris Johnson for targeted sanctions on Russian military officers over Moscow's support for the Syrian regime.

Ministers at the G7 meeting wanted more evidence of the attack to be collected before supporting the measure.