Chemical weapons may soon be released by the Assad regime in a large scale attack in Syria, U.S. officials told the Wall Street Journal in a report published Sunday. U.S. intelligence agencies have been focused on analyzing the type of chemical that could be deployed and what could trigger its use, officials who were briefed on the situation disclosed.

Officials reportedly suspect the Assad regime has created chemical bombs with chlorine gas and also may have the supplies to create weapons with nerve agent sarin, an even more lethal poison that is without taste, color or odor, and VX. These weapons had been believed eliminated when stockpiles were destroyed last August.

Syrian President Bashar Assad agreed to turn over his chemical arsenal in the face of international pressure and threats of U.S. airstrikes in retaliation for a sarin gas attack on Aug. 21, 2013. That large-scale attack caused the deaths of 1,400 people, including children, in the town of Ghouta.

But since the destruction, there have been reports of the Syrian government creating and using chemical weapons. In March, chlorine bombs reportedly were released in Binnish, a town outside the city of Idlib, injuring at least 30 people. Earlier that month, the United Nations condemned the use of chemical weapons, such as chlorine, and said perpetrators would be held responsible.

The latest intelligence, reported by the Journal, is “being taken very seriously,” a senior U.S. official said. That concern is in part due to desperate state the U.S. believes the Assad regime has reached. Assad’s army has been losing its top foreign advisers, both from Russia and Iran, and the U.S. has been training opposition fighters in Jordan and Turkey.