BEIJING, May 2 (Xinhuanet) -- Health officials in Turkey have said they are testing blood samples taken from n casualties to determine whether they were victims of a chemical weapons attack.

Dr Ubada Alabrash, Union of Syrian Medical Relief Organization, said, "When wounded people arrived at the Bab-al Hawa crossing they were suffering from suffocation, breathing difficulties, they were vomiting and large tears welled up from their eyes. These are symptoms of chemical gas. We cannot be certain but we are waiting for blood test results from the Turkish government."

The samples were sent to Turkey’s forensic medicine institute after several Syrians with breathing difficulties were admitted to a Turkish hospital in the town of Reyhanli along the Syrian border on Monday. The patients had been brought across the border from Idlib province in northern Syria.

On Tuesday, US President said there was evidence that chemical weapons had been used during the Syrian conflict. But that it was not yet clear how the chemical weapons were used, when they were used and who used them.

Washington has long said it views the use of chemical weapons in Syria as a "red line", but has said it wants proof before taking any action.

(Source: CNTV.cn)