A French Rafale fighter aircraft pilot lands on the French Charles-de-Gaulle aircraft carrier, after a flight on November 23, 2015 at the eastern Mediterranean sea, as part of operation Chammal in Syria and Iraq against the Islamic State group (AFP)

A French Rafale fighter aircraft pilot lands on the French Charles-de-Gaulle aircraft carrier, after a flight on November 23, 2015 at the eastern Mediterranean sea, as part of operation Chammal in Syria and Iraq against the Islamic State group (AFP)

A cyclist rides his bike across a snow covered field in the Basque mountain port of Opakoa, northern Spain, November 23, 2015 (Reuters)

A Belgian soldier patrols in Brussels' Grand Place as police searched the area during a continued high level of security following the recent deadly Paris attacks, Belgium, November 23, 2015 (Reuters)

An handout picture taken on November 24, 2015 and released by Make It Kenya shows riders cycling in a group downhill towards Timau town in Laikipia County, 250km north of the Kenyan capital Nairobi, on the fourth and final day of the Mt. Kenya Epik cycling ch (AFP)

A woman poses for pictures in a light display during a photocall at Kew Gardens in south west London, on November 24, 2015 (AFP)

Armed Syrian Turkmen villagers are seen near the northern Syrian village of Yamadi, near the Turkish-Syrian border, Syria, November 24, 2015 (Reuters)

Police help to make way for an ambulance carrying bodies after an attack on a military bus in Tunis, Tunisia November 24, 2015 (Reuters)

Italian Prime Minister Matteo Renzi makes a speech on the theme "A response to terror" during a news conference in Rome November 24, 2015. (Reuters)