WASHINGTON — France’s foreign minister on Tuesday accused the Syrian government of President Bashar Assad of attacking its people with chemical weapons at least 14 times since last October, including as recently as a few weeks ago.

At a Washington news conference, top French diplomat Laurent Fabius cited “credible witnesses” to the attacks, which he said included the use of chlorine gas. He said it has been difficult to garner definitive proof because chlorine gas generally evaporates too quickly to collect samples.

Under an agreement struck last summer, and to avoid US airstrikes, Assad was supposed to dismantle his government’s stockpile of chemical weapons by June 30. Currently, officials believe 92 percent of the stockpile has been shipped out of Syria to be destroyed at sea.

But Fabius said Syrian facilities that produce chemical weapons have not been destroyed, and he accused Assad’s government of not being fully forthcoming with the West about its continued ability to use toxic chemicals against opponents.

The suspected chlorine attacks, for example, “shows that the regime of Bashar Assad is still capable of producing chemicals weapons, and determined to use them,” Fabius told reporters.

He described the 14 attacks since last October 25 as “small-scale” and not likely to spur a Western military response.

It’s widely suspected that a chlorine gas attack sickened dozens of people last month in areas controlled by rebel forces that are seeking to oust Assad in the bloody civil war that has killed at least 150,000 people. But Western officials so far have been unable to offer any concrete proof of the attack, or that Assad’s troops launched it.

The Organization for the Prohibition of Chemical Weapons, which monitors the implementation of the Chemical Weapons Convention, sent a team to Syria this month to investigate the chlorine claims.

In a report Tuesday, Human Rights Watch said that forces loyal to Assad likely used chlorine gas packed into crude bombs in attacks in mid-April on three towns near a military base in northern Syria. Those attacks killed at least 11 people, and wounded as many as 500, it said.

Chlorine gas in bombs is not very lethal, but HRW said it appeared to have been used to terrorize residents and cause widespread panic.

Fabius also signaled some frustration with US and British refusals to launch airstrikes against Assad after a massive chemical weapons attack last August that killed at least several hundred people, and potentially as many as 1,400. He cited President Barack Obama’s “red line” pledge to order a harsh response if Assad launched toxic chemicals against his own people, but said Paris could not alone respond once Washington and London backed off the threat.

“It was out of the question for France to act alone,” Fabius said. “We regret that, because we believe it would have changed many things, in many respects.”

France is pushing the United Nations to refer Assad and his top officials to the International Criminal Court for crimes against humanity, and Fabius said a UN Security Council vote could come as soon as Tuesday. But it’s likely that Russia, which is a permanent Security Council member, will veto the move.

Fabius, speaking in English and French, also lambasted as “a tragical mockery” the Syrian presidential elections set for June 3 that Assad is expected to win. He said France, like Germany, has decided it will not help facilitate the vote among Syrian populations in their respective counties.

Copyright 2014 The Associated Press.