Syria’s government still has poison gasses, the Organization for the Prohibition and Chemical Weapons has found, despite its vows to eliminate the program.

Reuters reports that samples taken by OPCW experts in December and January tested positive for chemical precursors needed to make toxic agents.

“This is a pretty strong indication they have been lying about what they did with sarin,” one diplomatic source told the news agency.

In 2013, Bashar al-Assad’s regime promised to surrender all its chemical weapons after a deadly poison gas attack in a suburb of Damascus threatened Western intervention in Syria’s civil war, now in its fourth year. American president Barack Obama had previously warned that the use of chemical weapons constituted a “red line” that would trigger the United States’ involvement in the conflict.

Although Assad’s regime denied it had used chemical weapons, it jumped on a suggestion from its ally Russia to cooperate with an international effort to remove what was believed to be the Middle East’s largest arsenal of such weapons.

The OPCW, headquartered in the Netherlands, said last year the removal effort was complete. But its chief, Ahmet Üzümcü, cautioned that it was impossible to say if Syria had actually declared all its poison gasses. “All we can do is work on the basis of verifying a country’s declarations of what they have,” he told reporters at the time.

Experts warned Syria might only declare its outdated weapons and secretly keep its more sophisticated chemicals. The American Interest‘s Adam Garfinkle predicted that Assad would “keep the newer, more usable and lethal munitions and con us into being a hazmat garbage collector for the rest of the militarily marginal toxic junk that had piled up over the decades — and we’d foot the bill.”

The effort also forced Western countries into a coalition with a regime they claimed to oppose, since it was the only faction in Syria capable of providing the security needed to remove the weapons. The opposition is hopefully divided between relatively moderate and radical Islamist groups while a Kurdish minority in the northeast does battle with both regime and rebel forces.

Another unintended consequence of the operation was that China, Iran and Russia all took advantage of what they saw of Obama’s unwillingness to follow up on his threats, Garfinkle argues today.

Having taken the measure of the man in the White House, the Iranian regime increased its meddling in the Arab world […] and presaged the Houthi takeover of Yemen. The Chinese declared a new Air Defense Identification Zone and started earth-moving activities in the South China Sea. The Russians annexed Crimea and invaded Ukraine with little green men.

Whatever the scale of Syria’s remaining chemical weapons arsenal, Assad continues to deploy other brutal tactics against civilians and his opponents, including dropping barrels bombs on populated areas and withholding food and medicine from rebel areas.

While it is impossible to say how many Syrians have died in the conflagration since early 2011, opposition groups put the total at anywhere between 220,000 and 314,000.