BRUSSELS - NATO Secretary-General Anders Fogh Rasmussen said on Friday the world had made clear that any use of chemical weapons in Syria was unacceptable and a breach of international law."This is ... a matter of great concern," he told reporters after talks in Brussels with Moldovan Prime Minister Iurie Leanca. "The international community has made clear that any use of chemical weapons is completely unacceptable and a clear breach of international law."The White House said on Thursday that US intelligence agencies had concluded that Syrian President Bashar Assad's forces had used chemical weapons on a small scale against rebel fighters in Syria's civil war.