A Syrian firefighter is seen inside the destroyed Scientific Research Centre in Damascus, Syria April 14, 2018. REUTERS/Omar Sanadiki
The U.S. Navy guided-missile cruiser USS Monterey fires a Tomahawk land attack missile April 14, 2018. U.S. Navy/Lt. j.g Matthew Daniels/Handout via REUTERS
Syrian firefighters are seen inside the destroyed Scientific Research Centre in Damascus, Syria April 14, 2018. REUTERS/Omar Sanadiki
A Tornado pilot checks the weapons on his plane, in Akrotiri, Cyprus April 13, 2018. UK MOD Crown 2018/Handout via REUTERS
Bashar Jaafari, permanent Representative of the Syrian Arab Republic to the United Nations, shakes hands with Russian Ambassador to the United Nations Vasily Nebenzya at the end of the emergency United Nations Security Council meeting on Syria at the U.N. headquarters in New York, April 14, 2018. REUTERS/Eduardo Munoz
U.S. President Donald Trump makes a statement about Syria at the White House in Washington, April 13, 2018. REUTERS/Yuri Gripas
A Syrian soldier waves Russian and Syrian flags during a protest against air strikes in Damascus, Syria April 14, 2018. REUTERS/Omar Sanadiki
A girl sits in the aisle of a bus carrying Central American migrants, part of a caravan moving through Mexico toward the U.S. border, on a highway in Veracruz, Mexico April 6, 2018. REUTERS/Henry Romero
Central American migrants sleep at a sports centre in Matias Romero, Mexico April 5, 2018. REUTERS/Henry Romero
Children of Central American migrants wait in line to receive food in Matias Romero, Mexico April 3, 2018. REUTERS/Henry Romero
Central American migrants participating in a caravan heading to the U.S. take a pause from the journey in Matias Romero, Oaxaca, Mexico, April 2, 2018.
REUTERS/Jose de Jesus Cortes
Central American migrants, moving in a caravan through Mexico, disembark from a freight train as they walk on a railway track after stopping the train on a rail line, in Irapuato, Guanajuato state, Mexico April 15, 2018. REUTERS/Edgard Garrido
Central American migrants, moving in a caravan through Mexico, disembark from from a freight train as they walk on a railway track after stopping the train on the rail line, in Irapuato, Guanajuato state, Mexico April 15, 2018. REUTERS/Edgard Garrido
Central American migrants, part of a caravan moving through Mexico toward the U.S. border, gather on a sports field before boarding a bus bound for Puebla, in Matias Romero, Mexico April 5, 2018. REUTERS/Edgard Garrido
Central American migrants, part of a caravan moving through Mexico toward the U.S. border, stretch their legs during a stop on their route to Puebla, on a highway in Veracruz, Mexico April 6, 2018. The sign reads “Parking for heavy vehicles”. REUTERS/Henry Romero