A Syrian medical expert has defected to Turkey and claims he has evidence that President Assad’s regime used chemical weapons in an attack near Aleppo in March.

Dr Abdeltawwab Shahrour who is head of the forensic medicine committee in Aleppo was expected to reveal the details of the attack during a press conference in Turkey but was unable to appear due to “security concerns.” His documents are said to include eye-witness police accounts.

The attack at Khan al-Assal in the northern province of Aleppo killed more than two dozen people. Both government and rebels blame each other for what they say was an assault involving chemical weapons.

In the meantime, the Syrian opposition claims it has received information about government convoys carrying chemical weapons with one reaching a military airport near Damascus and another arriving near Deraa.

The head of the Syrian National Coalition, Khaled Saleh, said: “We received information in the last couple of days, that there were three convoys that were carrying chemical weapons, rockets with chemical heads, left their locations and now we can confirm, that two of them arrived at their final destination” .

Israel has been defending its earlier testing of missile launchers in the Mediterranean close to Syria.

The missiles were detected by Russian radar earlier triggering an alert across the region.

Israel says it is necessary for its army to carry out training to maintain its edge.

Western warships have been gathering in the Mediterranean and the Red Sea ahead of an expected attack against Syria.