The White House said Monday there are “indications” that in the month of April chemical weapons were again used in Syria, but that it is unclear if the Assad regime was responsible. The Obama administration claims it is now investigating who was behind the attack, though French President Francois Hollande said France also had information the regime is still using chemical weapons.

Last year, Bashar Assad promised to ship chemical weapons out of his country following a sarin gas attack that President Obama said was a “red line.” However, after botching a push for an “extremely limited strike” on the Syrian regime, the president was rebuked by members of both parties in Congress. The president quickly walked-back the threats of military force even before the agreement was reached, which was brokered by Russian President Vladimir Putin.

The latest attack was allegedly carried out on April 11 in the rebel-controlled village of Kfar Zeita, casting doubt on the claim rebels could have potentially been responsible.

“We have indications of the use of a toxic industrial chemical — probably chlorine — in Syria this month in the opposition-dominated village of Kfar Zeita,” State Department spokeswoman Jen Psaki said Monday.

“We’re examining allegations that the government was responsible. We take all allegations of the use of chemicals in combat use very seriously.”

White House Press Secretary Jay Carney echoed her statement shortly thereafter at the daily White House press conference, stating the event was “being investigated.”

Carney claimed after more information is known, the president and his administration will discuss “what reaction, if any” there would be from the international community, not what unilateral action the U.S. would take. He noted that under last year’s deal, 65 percent of Syria’s chemical weapons stockpiles have been removed for destruction, and “that process continues.” But Syria, since the agreement was reached, has been negligent and late on several set deadlines. Following the president’s lack of resolve in Ukraine, Assad even seemed to be contemplating whether or not to allow U.N. convoys back in the country.

Yet, all Jay Carney said at the briefing was that the new allegations are “of concern.” Meanwhile, both sides in Syria’s civil war blamed each other for the attack in Kfar Zeita.

Rebel activists from Kfar Zeita posted videos that mirrored earlier images, hoping to excite a world outcry exceeding the pressure on the West from last year. The video showing pale-faced men, women and children gasping for breath at a field hospital, while exhibiting excretions symptomatic of a chemical weapons attack, notably sarin gas.

The Syrian National Coalition, who enjoys support from the West, said the poison gas attack injured dozens of people. However, they declined to mention the specific gas used in the attack.

The Britain-based Syrian Observatory for Human Rights, an activist group that relies on a network of on-the-ground volunteers, said the gas attack happened during air raids that left heavy smoke over the area. It reported that people suffered from suffocation and breathing problems after the attack.

Naturally, Syrian state-run media blamed members of the Al Qaeda-linked Nusra Front rebel group, claiming the gas used was chlorine and that it killed two people and injured more than 100 others. Despite its apparent certainty, the state-run media did not mention how exactly it managed to confirm chlorine gas was used in the attack.

Chlorine, as a gas, can be extremely deadly, as the German army demonstrated by their use of it in World War I. In the Geneva Protocol of 1925, which Syria signed prior to Assad yet is still bound by, supposedly eliminated its use in battle through international ban.