The global chemical weapons watchdog has said it found traces of sarin following an attack in northern Syria in late March, days before a deadly strike using the same nerve agent in another Syrian town.

The Syrian army said the Israeli jets fired several missiles while in Lebanese air space.

Evidence suggests Assad was behind this week’s chemical weapons attack. Leaders are saying it is a redline issue but Western powers are at a loss to respond, says Peter Apps

While most of the world has agreed to destroy these deadly weapons, the attack in Syria this week shows the urgency of the situation, writes Caroline Alexander

UN ambassadors from Britain and France have said they will seek to punish members of the Syrian regime implicated in the use of chemical weapons during the country's civil war.

The use of chemical weapons is “becoming routine in the Syrian civil war”, a US official has said.

The Islamic State group is pursuing development of chemical weapons, setting up a branch dedicated to research and experiments, according to Iraqi and US intelligence officials.

The Islamic State group is aggressively pursuing development of chemical weapons, setting up a branch dedicated to research and experiments with the help of scientists from Iraq, Syria and elsewhere in the region, Iraq and US intelligence officials said.

French prime minister Manuel Valls has warned that Islamic extremists might at some point use chemical or biological weapons as he urged politicians to extend a national state of emergency by three months in response to last week’s Paris attacks.

The United States is investigating whether the Islamic State (IS) group used chemical weapons, following claims that the terror group deployed them against Kurdish forces in northern Iraq.

One hundred years ago this week chemical weapons were used for the first time, opening up a new chapter in conflict. Ann Cahill talks to some of the troops still cleaning them up