A top US intelligence chief has confirmed that ISIS have developed and used chemical weapons in Iraq and Syria, saying that its the first such attack by the group in over 20 years. The Director of National Intelligence, James Clapper, testified before the Senate Armed Services Committee confirming that mustard gas has been used by ISIS militants. Foxnews.com reports: He did not elaborate on where and when the chemical attacks occurred, though there has been mounting evidence the terror group was experimenting with chemical weapons. “[The Syrian government] has used chemicals against the opposition on multiple occasions since Syria joined the Chemical Weapons Convention. ISIL has also used toxic chemicals in Iraq and Syria, including the blister agent Sulfur mustard,” Clapper said. He said this marks the first time an extremist group has produced and used a “chemical warfare agent in an attack since Aum Shinrikyo used sarin in Japan in 1995,” referring to the Tokyo subway terror attack that year. Fox News previously reported on ISIS’ potential experimentation with chemical weapons. Photos taken by the Kurds in northern Iraq last summer and reviewed by Fox News showed burns and blistering on skin following exposure to “odorless, colorless” agents absorbed through the clothing. [...]