The death toll in the suspected chemical attack on a northern Syrian town rose to 72 on Wednesday even as Russia defended Damascus in face of an international outcry.
Activists and rescue workers found more terrified survivors hiding in shelters near the site of the harrowing assault, one of the deadliest in Syria's six-year long civil war.
Even as the rescue operation was underway, renewed airstrikes hit the town of Khan Sheikhoun in Idlib province, according to a Syrian opposition group.
The United States has blamed the government of President Bashar Assad for the attack saying that his patrons, Russia and Iran, bore "great moral responsibility" for the deaths.
The Damascus and Moscow denied they were behind the attack. A Russian Defense Ministry statement later said the toxic agents were released when a Syrian airstrike hit a rebel arsenal.
The attack on Khan Sheikhoun killed dozens of people on Tuesday, leaving residents gasping for breath and convulsing in the streets and overcrowded hospitals. Videos from the scene showed volunteer medics using fire hoses to wash the chemicals from victims' bodies.
Haunting images of lifeless children piled in heaps reflected the magnitude of the attack, which was reminiscent of a 2013 chemical assault that left hundreds dead and was the worst in the country's ruinous six-year conflict.
Syrian doctors said a combination of toxic gases is suspected to have been released during the airstrikes, causing the high death toll and severe symptoms.
The World Health Organization said victims of the attack appear to show symptoms consistent with exposure to a nerve agent.
In a statement, the agency said "the likelihood of exposure to a chemical attack is amplified by an apparent lack of external injuries reported in cases showing a rapid onset of similar symptoms, including acute respiratory distress as the main cause of death."
The Britain-based Syrian Observatory for Human Rights said 20 children and 17 women were among the 72 killed. Abu Hamdu, a senior member of the Syrian Civil Defense in Khan Sheikoun said his group has recorded 70 deaths.
He said his team of rescuers was still finding survivors, including two women and a boy hiding in an underground shelter beneath their home.
Russia defends ally Syria
Syria's government had earlier denied it carried out any chemical attack. But early on Wednesday, Russia, a major ally of the Syrian government, alleged a Syrian airstrike hit a rebel arsenal, releasing the toxic agents.
The Russian Defense Ministry spokesman, Maj. Gen. Igor Konashenkov, said in a statement that Russian military assets registered the strike on a weapons depot and ammunition factory on the town's eastern outskirts. Konashenkov said the factory produced chemical weapons that were used in Iraq.
Wednesday's renewed airstrikes hit not far from the location of the suspected chemical attack, said Ahmed al-Sheikho, of the Idlib Civil Defense team. He said the strikes did not cause any casualties because the area had been evacuated following Tuesday's attack.
The province of Idlib is almost entirely controlled by the Syrian opposition. It is home to some 900,000 displaced Syrians, according to the United Nations. Rebels and opposition officials have expressed concerns that the government is planning to mount a concentrated attack on the crowded province.
Pope Francis said during his general audience that he was "watching with horror at the latest events in Syria," and said he "strongly deplored the unacceptable massacre."
"I was watching with horror at the latest events in Syria. I strongly deplore the unacceptable massacre that took place yesterday in the Idlib province, where tens of defenceless people were killed, including many children. I pray for the victims and their families, and I appeal to the conscience of those with political responsibility both locally and internationally to cease this tragedy and bring relief to that dear population that for too long has been exhausted by war. I encourage, furthermore, efforts of those who, even amid insecurity and discomfort, strive to allow aid to reach the inhabitants of that region."
Earlier, President Donald Trump denounced the attack as a "heinous" act that "cannot be ignored by the civilized world." German Foreign Minister Sigmar Gabriel called on Russia to endorse a planned Security Council resolution condemning the attack.
Secretary of State Rex Tillerson also pointed the finger at the Assad regime, saying "it is clear that this is how Bashar al-Assad operates: with brutal, unabashed barbarism."
British Foreign Secretary Boris Johnson said "all the evidence" he had seen so far in the latest chemical weapons attack in Syria "suggests this was the Assad regime ... (that) did it in the full knowledge that they were using illegal weapons in a barbaric attack on their own people."
French president Francois Hollande condemning the attack and called it a "war crime."
Hollande recalled that France had pushed for an international military campaign against Syrian President Bashar Assad over his use of chemical weapons in 2013. France has supported Syrian rebels against Assad for years.
"France has not changed its position on this issue", he said according to Le Foll.
The EU Council president Donald Tusk said Tuesday's attack in Khan Sheikhoun is "another reminder of the brutality" of Syria's regime and the perpetrators must be held accountable.
Tusk said Wednesday that the Syrian regime bears "the primary responsibility for the atrocities," but also blamed supporters of President Bashar Assad's government who he said share the "moral and political responsibility."
UN Security Council to hold emergency meeting
The U.N. Security Council was to hold an emergency meeting on Wednesday in response to the strike and in Brussels, officials from 70 nations gathered for a major donors' conference on the future of Syria and the region.
Over 320,000 people have been killed in Syria since the conflict began in March 2011 with anti-government protests.
Claims of chemical weapons attacks, particularly the use of the chlorine agent, are not uncommon in Syria's conflict. The worst attack was what a U.N. report said was an attack by toxic sarin gas in August 2013 on the Damascus suburb of Ghouta that killed hundreds of civilians.
The New York-based Human Rights Watch has accused the Syrian government of conducting at least eight chemical attacks using chlorine gas on opposition-controlled residential areas during the final months in the battle for Aleppo last year that killed at least nine civilians and injured 200.
Also, a joint investigation by the United Nations and the international chemical weapons watchdog determined the Syrian government was behind at least three attacks in 2014 and 2015 involving chlorine gas and the Islamic State group was responsible for at least one involving mustard gas.
(With AP inputs)