UNITED NATIONS (AP) — New evidence indicates that the Syrian government used suspected nerve agents in four chemical weapons attacks since December as part of a broader pattern of chemical weapons use, a human rights group said Monday.
Human Rights Watch said in a report that the "widespread and systematic" attacks on civilians using chemical weapons could constitute crimes against humanity.
"The government's recent use of nerve agents is a deadly escalation — and part of a clear pattern," said Kenneth Roth, executive director of Human Rights Watch. "In the last six months, the government has used warplanes, helicopters and ground forces to deliver chlorine and sarin in Damascus, Hama, Idlib and Aleppo."
This also shows "that serious use of chemical weapons is becoming a central part of its military strategy," he said during a news conference to present the report.
The rights group said the four attacks using suspected nerve agents all took place in areas where offensives by armed groups fighting the government — including the Islamic State extremist group — threatened military air bases.
In an April 4 attack in the opposition-held town of Khan Sheikhoun in Idlib province, Human Rights Watch said 92 people, including 30 children, were identified by residents and activists as victims of deadly exposure to the nerve agent sarin, which Britain and France identified by chemical analysis. Medical personnel reported that hundreds more were injured, it said.
The Syrian government has repeatedly denied using chemical weapons and so has its close ally Russia, which has also carried out aerial attacks.
The report said two remnants at a crater in Khan Sheikhoun where the first bomb hit appeared to come from a weapon produced by the former Soviet Union that was used to deliver chemical agents.
Roth wouldn't speculate on whether it was part of Syria's undisclosed chemical stockpile or newly delivered. But he said Russia's claim that the civilians who died at Khan Sheikhoun were killed by toxic agents released from a rebel chemical arsenal struck by Syrian warplanes has "zero credibility."
As for the other attacks, the rights group said that after planes attacked northern Hama on March 30 and territory controlled by Islamic State extremists in eastern Hama on Dec. 11 and 12, witnesses described symptoms consistent with exposure to nerve agents that they and other local residents experienced.
In December attacks on Jrouh and Al-Salaliyah, Human Rights Watch said four witnesses interviewed by phone and two medical personnel interviewed by text messages through intermediaries gave consistent accounts of nerve agent attacks. An opposition-affiliated activist and residents provided the names of 64 people who died of chemical exposure, it said.
The group quoted residents, medical personnel and first responders saying the suspected attack on Al-Lataminah on March 30 caused no deaths but reportedly injured 169 people, both civilians and combatants.
It also gave details of eight chlorine attacks since January that killed three people and injured almost 150 including six combatants. Roth said in the last two days there have been two other incidents of reported chlorine use.
As part of the evidence showing that attacks have become widespread and systematic, Human Rights Watch identified three different systems being used to deliver chemical weapons:
—Government warplanes dropping bombs with nerve agents.
—Government helicopters dropping chlorine-filled munitions, which has become more systematic.
—Government or pro-government ground forces using improvised ground-launched rockets filled with chlorine since January. Human Rights Watch said it has documented six separate uses of such rockets in four different areas in the Damascus suburban area.
In at least some attacks, the rights group said, the aim appears to have been to inflict "severe suffering" on the civilian population.
Roth said Syria has apparently escalated to using nerve agents since its extensive use of chlorine for many months provoked very little reaction — "and that kind of impunity apparently encouraged a ratcheting up of the chemical agent used."
Human Rights Watch called on the U.N. Security Council to impose an arms embargo on Syria and sanctions on those in the military responsible for chemical attacks — and to refer Syria to the International Criminal Court.
Russia has vetoed eight council resolutions backed by the West on Syria, including one last month that would have condemned the attack on Khan Sheikhoun and called for an investigation and another in May 2014 that would have referred the Syrian conflict to the ICC. China joined in vetoing six of the resolutions.
Roth said if Russia and China continue to block a referral, the U.N. should move ahead "expeditiously" to establish an investigative body approved by the General Assembly in December to assist in documenting and prosecuting the most serious violations of international law in Syria, including possible war crimes and crimes against humanity.