Brussels: NATO Secretary General Anders Fogh Rasmussen said Friday that any use of chemical weapons in Syria was "completely unacceptable" and was a breach of international law.
The remarks came after the White House announced the Syria government had used chemical weapons against rebels.
"This is indeed a matter of great concern. The international community has made clear that any use of chemical weapons is completely unacceptable and a clear breach of international law," Rasmussen told reporters at the NATO headquarters.
"I welcomed the clear US statement. It is urgent that the Syrian regime should grant access to the United Nations to investigate all reports of chemical weapons use," he said.
On Thursday, the White House said in a statement the Syrian government had used chemical weapons against rebels, a major move that signals deeper US involvement in the Syrian conflict.
Rasmussen said he still believed a political solution was the right way forward in Syria and urged all parties involved, the Syrian government and the opposition to attend an international conference proposed by the US and Russia jointly.