U.N. chemical weapons investigators confirmed the deployment of deadly sarin gas in an attack on the Damascus suburbs in August, but did not assign blame for the attack to either regime or rebel forces. Mohamed Abdullah/AFP/Getty

Syria on Wednesday missed a deadline to hand over all of its declared toxic materials to the world's chemical-weapons watchdog, putting a program to destroy the war-torn country’s stockpile several weeks behind schedule and jeopardizing its final June 30 deadline.

On the same day, Libya confirmed it had at long last destroyed the entirety of its chemical-weapons stores, 10 years after former dictator Muammar Gaddafi signed the U.N. chemical-weapons convention, a grim reminder that such cleanups nearly always take longer than expected.

Under a deal reached in October between Russia and the United States, which helped avert a U.S.-led missile strike against the regime of President Bashar al-Assad, Syria had agreed to give up its entire stockpile of chemical weapons by Feb. 5.

But due to extended delays, which chemical-weapons cleanup experts predicted, Syria has relinquished control only of slightly more than 4 percent of weapons it reported to the Organization for the Prohibition of Chemical Weapons (OPCW).

There have been no additional shipments since Jan. 27 and the government has failed to provide a revised schedule, said OPCW spokesman Michael Luhan.

"It's a status quo until we get this plan,” he told Reuters.

Damascus has blamed the delay on security problems and the threat of attacks by rebels on road transports to the northern port of Latakia, and has requested additional armor and communications equipment.

As the operation inches along, the Assad regime continues to frame itself as a partner in peace to the foreign powers wrangling for a resolution to Syria’s nearly three-year civil war, which has killed upwards of 130,000 people. By agreeing to dispose of its chemical weapons, the regime has also staved off the threatened U.S.-led strike, which was prompted by a sarin gas attack on the outskirts of Damascus in August that killed hundreds of civilians. The U.S. and its allies blamed the regime for the attack.

In a statement last week, U.S. representative to the OPCW Robert Mikulak suggested the Assad regime was dragging its feet intentionally and exploiting the chemical cleanup as a bargaining chip.

"Syria has said that its delay in transporting these chemicals has been caused by "security concerns" and insisted on additional equipment —armored jackets for shipping containers, electronic countermeasures and detectors for improvised explosive devices," Mikulak wrote. "These demands are without merit and display a 'bargaining mentality' rather than a security mentality."

While Russia said on Tuesday that its ally Syria would transport more chemicals soon, Western diplomats said they saw no indications that further shipments were pending.