A British man is being questioned in France on suspicion of slitting the throats of his two children, local police said.
The recently divorced man is alleged to have killed the chidren - aged five and ten - after he was entrusted with them for the first time since separating from his wife.
Their bodies were discovered in a flat in a suburb of Lyon yesterday afternoon.
The man, who has not been named, was taken into custody after his former wife arrived at the building to find him on the stairs wearing blood-stained clothes, according to local reports.
A police source said: "We believe the man was looking after the children for the first time since he divorced his wife.
"He was arrested at the end of yesterday afternoon."
A spokesman for the British Foreign Office said: "We are aware of the reports and we are looking into them."