Russia has deployed several more warships to the Mediterranean Sea, in what Russian media are calling the largest naval buildup since Russia entered the Syrian civil war in 2015.
The reinforcement comes as Russia's ally, Syrian President Bashar al-Assad, is believed to be preparing an assault on the last major enclave held by rebels, Syria's northern Idlib province, and the UN's humanitarian director warned on August 28 that a large-scale government offensive there "has the potential to create a humanitarian emergency at a scale not yet seen" in Syria's seven-year conflict.
It also comes as the United States, Britain, and France at a meeting of the UN Security Council on August 28 repeated their warning to Syria, whose army has been backed by Russian air power, not to use chemical weapons in an assault on Idlib, and said any use of such illegal weapons would result in Western retaliation.
Russia has cited the warning from Western powers in recent days in accusing the United States of building up its own forces in the Middle East in preparation for a possible strike on Syrian government forces -- something the Pentagon has denied.
The Russian accusations come even as media are reporting a major buildup of Russia's naval fleet in the Mediterranean. Reuters reported that on August 25, shipping records and photos show Russia's Admiral Grigorovich and Admiral Essen frigates sailed through Istanbul's Bosphorus Strait towards the Mediterranean.
It said the day before, the Pytlivy frigate and landing ship Nikolai Filchenkov were also pictured sailing through the Turkish straits that connect the Black Sea with the Mediterranean. The Vishny Volochek missile corvette passed through earlier this month.
The pro-Kremlin Izvestia newspaper said Russia is gathering its largest naval presence in the Mediterranean since it intervened in Syria in 2015, turning the tide in Assad's favor in a war that has killed over 400,000 people and displaced millions more.
The Russian naval force in the Mediterranean now includes 10 vessels, most of them armed with long-range Kalibr cruise missiles, Izvestia said, adding that more are on the way, and that two submarines have also been deployed.
At the United Nations, humanitarian director John Ging called on members of the UN Security Council "to do all they can to ensure that we avoid" a humanitarian crisis in Idlib, the Syrian province on the border with Turkey which is home to nearly 3 million people, including most remaining Syrian Sunni rebel fighters and their families.
Ging said recent weeks have seen "a further serious deterioration of the humanitarian situation," with intense bombing and shelling reported in parts of Idlib.
He said that "a worst-case scenario in Idlib will overwhelm capacities" of aid organizations, and "has the potential to create a humanitarian emergency at a scale not yet seen through this crisis."
Russian media quoted Russian Defense Minister Sergei Shoigu as saying on August 28 that the Russian military is trying to negotiate what he called a "peaceful settlement" with "moderate" rebel groups in Idlib like the one reached with rebel groups this year in eastern Ghouta outside Damascus, which would give them assurances of safety in exchange for the surrender of their weapons.
At the UN meeting, Russia again accused the extremist rebel group, the Al-Qaeda-linked Levant Liberation Committee, of preparing a chemical attack in Idlib, which Moscow says the West will use to justify a strike against Syrian forces.
Russia also claims British special forces are helping the rebels, including by possibly supplying chlorine gas, an illegal chemical weapon, prompting a sharp denial from Britain's UN Ambassador Karen Pierce.
"Even by the egregious standards of Russian propaganda, this is an extraordinary allegation," Pierce said. "It is wholly untrue."
She called the claim "fake news" and said it could be "a smoke screen for a possible impending [chemical] attack by the Syrian regime, once again against its own people, in Idlib."
"I repeat the statement that I, the French, and the Americans made earlier about responding appropriately," she said.
Pierce later told reporters "it's very clear to us and our partners that this is an effort to distract from an imminent attack on Idlib."
Russia's UN Ambassador Vasily Nebenzya said Syrian armed forces have no chemical weapons and there is no military need for them.
"People in their right minds will not use means that are useless from a military point of view in order to trigger reprisals by three major powers," he said.
"Thank you for this warning of your response," Nebenzya added. "We want to also warn you that we are absolutely aware of your unsavory plans. We strongly suggest that you refrain from them. Carrying out these plans will further deliver a strike against a peaceful resolution in Syria."
Pierce, who currently is presiding as president of the security council, said Russia is blocking attempts to form a consensus on the council to respond to Ging's plea for action to prevent a humanitarian disaster in Idlib.