Damaged cars and buildings are seen in besieged Eastern Ghouta, outside Damascus. (Bassam Khabieh/Reuters)

Syrian government forces defied a new U.N. Security Council resolution calling for a cease-fire on Sunday by launching a ground offensive, sustaining their airstrikes and allegedly dropping at least one bomb laden with chlorine against a rebel-held enclave outside Damascus.

Residents of the Eastern Ghouta suburb of Damascus spent a seventh consecutive day huddled in shelters as warplanes and artillery pounded the area, killing at least 22 and dashing hopes that this latest in a long string of failed efforts to tamp down the relentless bloodshed in Syria would work.

Among the dead was a child who suffocated when a chlorine bomb was dropped on a neighborhood in the suburb, the first chemical attack since the negotiations for a cease-fire began this month, according to doctors in the area.

“It was one more terrible day in Syria,” said Panos Moumtzis, the United Nations’ regional coordinator for Syria, who initiated the cease-fire call three weeks ago. He said he was “very, very disappointed” by Sunday’s violence but hoped a way to secure at least a temporary truce could still be found.

The United States and its allies had hailed as a diplomatic victory the unanimous vote in New York on Saturday approving a 30-day cease-fire, which was expected to go into effect “without delay.”

But to secure the support of Russia, the language of the resolution was diluted to exclude unspecified “terrorists,” a loophole that seems to be providing justification for continued fighting on many fronts. The Syrian government routinely describes all of its opponents as terrorists, even though only a small number of the armed groups fighting in Syria are designated as terrorists by the international community.

Apart from stating that the cease-fire should go into effect as soon as possible, the resolution provided no deadline, no mechanism for establishing one and no process for enforcing the truce should it take hold.

A top Iranian military official said that Iran and Syria would abide by the cease-fire resolution, but that the suburbs of Damascus would not be included because they are “under terrorists’ control.” Iran is one of President Bashar al-Assad’s closest allies and has provided much of the military support that has helped him prevail over the rebellion.

“The cleansing operation will continue in those areas,” said Maj. Gen. Mohammed Hossein Baqeri, chief of staff of the Iranian armed forces, according to Iran’s Tasnim news agency.

Turkey also said it would continue its offensive in the northern Syrian enclave of Afrin, where a separate battle is taking place. Afrin is controlled by a Kurdish group affiliated with the Kurdistan Workers’ Party, designated a terrorist organization by the United States and the United Nations, as well as by Turkey.

The Turkish armed forces “will remain resolute in fighting against the terrorist organizations that threaten the territorial integrity and political unity of Syria,” Turkish Foreign Ministry spokesman Hami Aksoy said.

But it was the plight of the estimated 350,000 civilians living in the besieged Damascus suburb of Ghouta that drove this latest effort in the United Nations to secure a pause in the fighting. The area has been surrounded by government forces for the past five years, leaving many residents not only under assault, but also short of food and medical supplies.

One of the main goals of the cease-fire, Moumtzis said, is to facilitate the delivery of much-needed food and medicine, available in warehouses nearby and poised for delivery the moment the government gives permission.

Instead, as the negotiations for a cease-fire got underway, the violence only intensified. More than 500 people have been killed in the past week alone as the government launched a renewed attempt to subdue the area, according to medical workers and monitors.

According to the U.S.-based Syrian American Medical Society, 180 people were killed in Ghouta, including 42 children, in just the 48 hours the Security Council spent debating the final language of the resolution — arguing “over commas,” according to Nikki Haley, the U.S. ambassador to the United Nations.

The United Nations issued an appeal to all parties to ignore the language on terrorism and heed their obligation under international law to protect civilians. “Efforts to combat terrorism do not supersede these obligations,” U.N. Secretary General António Guterres said in a statement.

Sunday’s attacks instead highlighted the continued helplessness of the international community to act to protect civilians from a war that has polarized the world and killed as many as 500,000 people over the past five years.

Starting at dawn, tanks and armored vehicles belonging to the government’s elite Tiger force militia rolled into three neighborhoods in the area, in an early indication that the cease-fire would go unheeded. The warplanes didn’t stop their bombardments even in the immediate hours following the cease-fire, residents said.

The use of a chlorine bomb, which killed the child and hospitalized nine others with breathing difficulties, according to the Syrian American Medical Society, seemed only to underline the government’s defiance, because halting the use of chlorine has been a focus of the United States’ most recent efforts to influence the course of the war.

“Nothing has changed on the ground. This is only a truce in the Security Council,” said Firas Abdullah, an activist with the Ghouta Media Center. “The warplanes are still hitting and people are still hiding. Nobody can go outside.”

Within just six miles of the capital, Ghouta is one of the largest rebel-held enclaves in the country and is the only one that poses a direct threat to Damascus. The rebels who control the area retaliated against the stepped-up airstrikes over the past week by firing volleys of mortars onto the city, killing at least six people and emptying streets in one of the only parts of the country that has remained relatively unaffected by the war.

In the absence of an international consensus on ways to secure a wider settlement to the conflict, there are few reasons to believe that Assad will halt an offensive against an area considered vital to consolidating his hold on power, said Charles Lister of the Middle East Institute in Washington.

“The Assad regime can literally taste strategic victory in its capital Damascus, and given that reality, it’s sadly very difficult to imagine any cease-fire in Eastern Ghouta holding for very long,” he said. “As far as the pro-regime alliance is concerned, taking back Eastern Ghouta would seal up a de facto strategic victory and end any possible serious threat to regime sustainability.”