French President Francois Hollande called Friday for the release of two French journalists missing in Syria, saying their lives were at risk.

Hollande, who is visiting Tokyo on a state visit, told reporters he could not give details about the two.

"Their lives are at risk, so I cannot say anything more," he said. "I want them released as soon as possible."

The French radio broadcaster Europe 1 said in a statement on its website that it was unable to get in touch with reporter Didier François and photographer Edouard Elias, who had been headed from the Turkish-Syrian border for Aleppo. Europe 1 said it was keeping in touch with French authorities in an effort to gain more information.

Hollande said it is essential that media be able to travel throughout Syria to help keep the world informed about the worsening humanitarian situation in the country, where civil war has killed tens of thousands of people.

He and Japanese Prime Minister Shinzo Abe pledged to work together to resolve the Syrian crisis.

Both urged a political resolution to the strife.

"Syria's future must be decided by the Syrian people," Abe said, pledging to increase humanitarian assistance for victims of the war.

The 27-nation European Union has imposed punitive measures on the regime of Syrian President Bashar Assad and, led by France and Britain, has begun to open the way to start sending arms to moderate opposition forces.