The United Nations has demanded an investigation into a suspected chemical weapons attack in Syria.
Hundreds of people are reported to have been killed in the attack, just outside the capital Damascus.
There are calls for UN weapons inspectors who are already in the city, to be allowed to investigate the site.
US President Barack Obama has said previously that if chemical weapons were used in Syria, it would force the rest of the world to take action.
Situation is unclear
It's extremely difficult to work out what's happened in Syria as both sides blame each other for attacks.
Rebel fighters claim that the Syrian government carried out the attack, but the government denies this, saying it was the rebels themselves.
If it's confirmed that chemical weapons have been used, it may mean other countries decide to get involved in Syria's war.
Chemical weapons, such as poison gases, are banned under international law because of the harm they can cause to people over a wide area.