DAMASCUS — Chemical weapons inspectors who came under attack while investigating claims of chlorine gas attacks in Syria last month found information suggesting that similar chemicals had indeed been used, the global chemical weapons watchdog said on Tuesday, June 17.

The Organization for the Prohibition of Chemical Weapons, which is overseeing the destruction of Syria’s chemical stockpile, said inspectors had information indicating chlorine gas-like chemicals were used despite having been forced to cut short their mission after the attack.

“Despite the grave incident, which prevented the fact-finding mission from conducting an important field visit, the team was able to prepare a preliminary report,” the organization said in a statement.

“The information that was available to the fact-finding mission lends credence to the view that toxic chemicals – most likely pulmonary irritating agents, such as chlorine —have been used in Syria,” the body said.

The inspectors, from a joint OPCW/United Nations fact-finding team, were traveling to the central province of Hama to investigate allegations of illegal chlorine attacks by government forces when their convoy came under attack. 

No team members were injured in the incident, which the Syrian government blamed on rebel fighters.

President Bashar al-Assad, whose forces have been battling rebels trying to unseat him for more than three years, agreed last year to hand over Syria’s entire chemical weapons stockpile after hundreds of people were killed in a sarin gas attack near Damascus.

Kurds in parts of northern Syria have carried out arbitrary arrests and failed to investigate the killings and disappearance of political opponents, Human Rights Watch said on Thursday in a report documenting rights abuses.

The Democratic Union Party (PYD), an offshoot of the Kurdistan Workers’ Party (PKK) in neighboring Turkey, has run three Kurdish enclaves in northern Syria since 2012, when Syrian government forces withdrew from the areas.

The PYD, which runs a local administration with courts, prisons, and police, could not be immediately reached by Reuters for comment on the report, which said the party had denied holding political prisoners.

In its first full report on the Kurdish enclaves, Human Rights Watch said it had found that children had been recruited into the PYD’s police force and armed wing. Kurdish opposition members have also been convicted in unfair trials and detainees have complained of abuse, the New York-based rights group said.

It said the harassment and arbitrary arrest of the PYD’s Kurdish political rivals was the biggest cause for concern.

The PYD denies holding any political prisoners and said the men whose cases the rights group documented were arrested for criminal acts, such as drug trafficking and bomb attacks, the report said.

Human Rights Watch has also reported serious human rights abuses by the Syrian government and other opposition fighters in the country since 2011. Some of those acts amount to war crimes and crimes against humanity, it says.

 Russia said on Tuesday it has gained Syrian approval to open four border crossings from Iraq, Jordan and Turkey to deliver aid to millions of people under a “far-reaching formula” proposed to U.N. Security Council members.

Russian U.N. Ambassador Vitaly Churkin declined to elaborate on the formula, but diplomats familiar with the plan said it involved using international monitors to inspect humanitarian aid convoys entering Syria.

Veto-wielding council members — the United States, Britain, France, China and Russia – have been negotiating a humanitarian resolution drafted by Australia, Luxembourg and Jordan to boost aid deliveries in Syria, including across rebel-held borders. Russia presented its formula to those seven states on Tuesday.

Australia labelled the plan as insufficient.

“What we’ve been given by the Russians, which is a big improvement over what they gave us a week ago, is not good enough,” Australian U.N. Ambassador Gary Quinlan told reporters. “It’s not ready.”