Britain and France say they will continue to push for a resolution at the United Nations to condemn the killing of dozens of civilians in northern Syria in an apparent chemical-weapons attack, as the United States has called on Russia to rethink its relationship with the Syrian government.
"I cannot understand how anybody on UN Security Council could fail to sign up to a motion condemning the actions of the regime that is almost certainly responsible for that crime," British Foreign Secretary Boris Johnson told reporters during a visit to Sarajevo on April 6.
Meanwhile, French Foreign Minister Jean-Marc Ayrault told CNews television that a new UN resolution should be a top priority. "France is still seeking to talk with its partners on the Security Council...Russia in particular," he said.
However, Ayrault said, "It's difficult because up to now every time we have presented a resolution, there has been a veto by Russia and sometimes by China."
Russia has given Syrian President Bashar al-Assad crucial diplomatic and military support throughout the 6-year-old war that began with a violent crackdown on pro-democracy protests and has killed more than 300,000 people.
Johnson and Ayrault's comments came after Russia rejected on April 5 a draft UN resolution on Syria drafted by the United States, Britain, and France amid mounting international outrage over alleged chemical air strikes on April 4 that the Britain-based Syrian Observatory for Human Rights says have killed 86 people in the town of Khan Sheikhoun, Idlib Province.
Turkey's state-run Anadolu news agency quoted Justice Minister Bekir Bozdag as saying on April 6 that the result of autopsies on three victims "confirms that [Syrian President Bashar al-]Assad used chemical weapons."
Bozdag said World Health Organization (WHO) experts took part in the autopsies conducted in Turkey. A spokesman for the UN health organization said "a WHO person was there at the time of the autopsy but had no role in the autopsy or investigation."
About 60 injured were brought to Turkey for medical treatment and three have subsequently died, reports said.
Moscow and Damascus claim that the toxic gas was released when air strikes by government forces hit a rebel weapons depot, an assertion the United States and others reject.
"This was a dangerous and monstrous crime," Kremlin spokesman Dmitry Peskov said on April 6. He claimed that "any information that the American side or our colleagues in other countries could have cannot be based on objective materials or evidence."
Earlier, the Russian Foreign Ministry said it was premature to accuse the Syrian government of responsibility for the deaths in Khan Sheikhoun and that a proper investigation was needed.
However, Russian President Vladimir Putin's spokesman said on April 6 that Moscow's support for Assad is not unconditional.
"Unconditional support is not possible in this world," spokesman Dmitry Peskov said in an exclusive interview with AP on April 6.
He added, however, "It is not correct to say that Moscow can convince Mr. Assad to do whatever is wanted in Moscow." Peskov said that Assad and his military are "the only real power in Syria that can resist terrorists on the ground."
At a press conference in Damascus, Syrian Foreign Minister Walid al-Muallem reiterated that the country's army "has not, did not, and will not use this kind of weapons -- not just against our own people, but even against the terrorists."
Assad's government refers to its opponents as terrorists.
Also on April 6, Turkey's state-run Anadolu news agency quoted Justice Minister Bekir Bozdag as saying that the result of autopsies on three victims "confirms that Assad used chemical weapons."
Bozdag said World Health Organization (WHO) experts took part in the autopsies conducted in Turkey. The UN organization did not immediately comment.
WATCH: Trump On Syria Attack
On April 5, U.S. Secretary of State Rex Tillerson said there was "no doubt in our mind that the Syrian regime, under the leadership of Bashar al-Assad, is responsible for this horrific attack."
"And we think it's time the Russians really need to think carefully about their continued support for the Assad regime," Tillerson added.
He was speaking the same day that the State Department announced he will visit Russia on April 12, the first trip there by the top U.S. diplomat since President Donald Trump took office in January.
Trump said on April 5 that Assad's government had gone "beyond a red line" with the attack, which he said "crosses many, many lines" and was "unacceptable."
"And I will tell you, it's already happened that my attitude toward Syria and Assad has changed very much," Trump said.
The U.S. president did not mention Russia in his remarks on the issue, but Tillerson was one of several senior administration officials who criticized Moscow over the attack.
Vice President Mike Pence said that "all evidence points" to the Syrian government being behind the attack, and called on Russia to honor its agreement to help eliminate chemical weapons in Syria.
Pence laid at least partial blame for the April 4 chemical attack on the administration of former President Barack Obama, saying it failed to hold Russia and Syria to the chemical-weapons ban Assad signed in 2013.
In an interview on Fox News on April 5, Pence said it was time for Moscow to "keep the word that they made to see to the elimination of chemical weapons so that they no longer threaten the people in that country."
WATCH: Russia 'Cannot Escape Responsibility' Over Syrian Attack
At the UN Security Council meeting on the issue, U.S. Ambassador Nikki Haley said that "if nothing is done, these attacks will continue. Assad has no incentive to stop using chemical weapons as long as Russia continues to protect his regime from consequences."
"Yesterday morning we awoke to pictures, to children foaming at the mouth, suffering convulsions, being carried in the arms of desperate parents," she said. "We saw rows of lifeless bodies, some still in diapers, some with visible scars of a chemical weapons attack. Look at those pictures. We cannot close our eyes to those pictures. We cannot close our minds of the responsibility to act."
Reuters reported on April 5 that U.S. intelligence officials, based on a preliminary assessment, said the deaths were most likely caused by sarin nerve gas dropped by Syrian aircraft on the town of Khan Sheikhoun.