(CNN) -

The final stockpile of Syria's chemical weapons has been shipped out of the country, according to the OPCW, the Organisation for the Prohibition of Chemical Weapons.

Ahmet Uzumcu, the chief of the international watchdog organization, said the weapons were loaded Monday aboard the Danish ship Ark Futura and departed the Syrian port of Latakia.

"A major landmark has been reached today," Uzumcu said, qualifying that that meant all "declared" weapons were out of the country.

"We cannot say for sure it has no more chemical weapons," Uzumcu said. "All we can do is work on the basis of verifying a country's declarations of what they have. I would not make any speculation to possible remaining assets, substances, chemical weapons. ... "

It has been more than a year since the Obama administration said that Syria had crossed a "red line" with its use of chemical weapons during the nation's civil war, which has raged since 2011.

In August 2013, U.N. spokesman Martin Nesirky told reporters that a team of experts had gathered to go to Syria to investigate reports of chemical weapons. Later that month, video and witness accounts appeared to support the allegations that scores of people killed outside the Syrian capital of Damascus had been poisoned with chemical weapons. The nonpartisan Doctors Without Borders then reported that three hospitals near Damascus treated more than 3,000 patients suffering "neurotoxic symptoms."

In September, U.N. Secretary-General Ban Ki-moon released the inspectors' report, which says there is "clear and convincing evidence" that sarin, a nerve agent developed for chemical warfare, was used in the Damascus attack.

Later that month, the U.N. Security Council passed a resolution requiring Syria to eliminate its chemical weapons arsenal, and Syrian President Bashar al-Assad promised to adhere to the resolution. The following month, Syria began dismantling its chemical weapons program.

The OPCW reported that Syrians were using torches and grinders to destroy or disable weapons such as missile warheads and aerial bombs.

But in February, the OPCW told CNN that Syria had shipped out only 11 percent of its chemical weapons stockpile.

That happened after a February deadline ordering that all chemical arms be removed from Syria had passed.

While Monday brought an apparent end to a chapter regarding Syria's chemical weapons, talks to achieve some semblance of peace in the country continue and, on the ground in Syria, trauma and bloodshed continue.

On June 20 in New York, Ban gave an impassioned speech about the war in Syria.

It's possible that more than 150,000 people have died since the war began, but the U.N. chief said it may be impossible to get an exact count of how many have lost their lives.

Half of Syria's population of 22 million has been displaced, and a flood of refugees are struggling to put their lives back together in neighboring countries such as Lebanon, Turkey, Jordan and Iraq, Ban said.

"The international community must not abandon the people of Syria and the region to never-ending waves of cruelty and crisis," he implored. "The greatest obstacle to ending the Syria war is the notion that it can be won militarily. ...

"No one is winning; no one can win. Even if one side were to prevail in the short term, the devastating toll will have sown the seeds of future conflict."