Syrian president Bashar al-Assad all smiles as he visits Russian air base despite US warnings

A picture released on the official Facebook page of the Syrian Presidency today shows President Bashar al-Assad sitting inside a Sukhoi Su-27 during his visit to the Hmeimim military base in Latakia province, in the northwest of Syria. Photo/Getty Images

Syrian president Bashar al-Assad grinned as he was shown around a Russian airbase in his wartorn country - shortly after US authorities warned he is planning another attack on his people.

Assad was greeted by officials at Russia's Hmeimim air base in western Syria, and was pictured climbing into the cockpit of a fighter jet.

It happened on a day when the Pentagon said it detected "active preparations" by Syria for a chemical weapons attack, giving weight to a White House statement hours earlier that the Syrian government would 'pay a heavy price' if it carried out such an attack, according to Daily Mail.

Syrian media has published pictures of Assad inspecting the base, and inside a Russian SU-35 plane.

He was accompanied by the Russian Army's Chief of Staff, Gen. Valery Gerasimov, at the site near the coastal city of Latakia.

The U.S. accusation and ominous warning marked a further escalation of tensions in a country where the U.S. is using Syrian Arab and Kurdish proxy soldiers to combat the Islamic State group in its remaining strongholds, even as Russia and Iran work to prop up President Bashar Assad, who has gained the upper hand in a long civil war.

A Pentagon spokesman, Navy Capt. Jeff Davis, said the U.S. had seen "activity" at Shayrat airfield that "indicated active preparations for chemical weapons use."

That is the same base from which the Syria air force launched an attack in April that the U.S. and others said used lethal chemicals to kill civilians. Syria denied the charge.

The White House said that the impending attack will likely harm "innocent children and civilians".

'The United States has identified potential preparations for another chemical weapons attack by the Assad regime that would likely result in the mass murder of civilians, including innocent children.

Assad was accompanied by the Russian Army's Chief of Staff, Gen. Valery Gerasimov, at the site near the coastal city of Latakia. Photo/Facebook

The activities are similar to preparations the regime made before its April 4, 2017 chemical weapons attack.

"As we have previously stated, the United States is in Syria to eliminate the Islamic State of Iraq and Syria.

"If, however, Mr. Assad conducts another mass murder attack using chemical weapons, he and his military will pay a heavy price," it said.

There was no further detail given of how the US will respond to a fresh attack.

If imminent, the attack would coincide with the end of Eid. President Assad greeted fellow worshipers as he left a mosque in Hama on Sunday to observe the holiday.

On April 4, 89 people died in a Sarin gas attack on the town of Khan Sheikhoun.

Photographs taken in the aftermath of the atrocity of children writhing in pain as adults frantically tried to clean their bodies with water bottles shocked the world.

The attack was so horrifying it prompted President Trump to launch missile strikes on one of the Assad regime's airbases.

Assad not only denied having any role in the attack but suggested that it was a hoax that had been thought up by one of his many enemies.

He suggested that the photographs which shocked the world including those of a grieving father weeping over his dead twin babies had been staged by terrorist groups eager to turn the West against him.

He was bolstered in his offensive claims by the Kremlin which also criticized how the blast site was handled after the atrocity.

US troops are already in Syria providing training and resources to Kurdish an Arab rebel forces in their ongoing fight against ISIS.

The Syrian president was pictured with Russian military officials inspecting the base in the west of the wartorn country. Photo/Getty Images

As the White House posted its warning on Monday, news emerged that a group of Kurdish fighters had seized al-Qadisiy, part of the ISIS stronghold Raqqa.

A spokeswoman for the group Syrian Democratic Force said it was the result of sustained airstrikes in the region since the start of the month.

Civilians in the region reported artillery and rocket launches on Monday. They shared their observations on the Facebook group Raqqa Is Being Slaughtered Silently, one of the few remaining ways for them to communicate with the rest of the world.

Assad's military conflict predates the spread of ISIS in Syria which now dominates news of the country's catastrophic state.

After his remarks about the April 4 attack, the parents of some of the children killed in it begged the rest of the world to expose him for the "lying criminal" they say he is.

One, whose twin babies died in the blast, told MailOnline of his anguish.

"How can he pretend that they are not dead? How? We saw them. We buried them with our own hands," Abdul Hamid al-Yousef said.

"I pray that all the governments of all the world do not believe the lies of this criminal regime," he added.

US President has warned that the Assad regime is planning another chemical attack. Photo/AP

President Trump was quick in his response to April's attack, authorizing the missile air strikes just three days later.

In an emboldened speech afterwards, he said: "Using a deadly nerve agent, Assad choked out the lives of helpless men, women and children.

"It was a slow and brutal death for so many. Even beautiful babies were cruelly murdered in this very barbaric attack.

"No child of God should ever suffer such horror."

Ivanka Trump said she was proud of the move, saying: "The times we live in call for difficult decisions."

It was later reported that the strikes had been ordered at her insistence after she saw the harrowing images from the attack site.

As the announcement spread on Monday, Trump carried on celebrating his Supreme Court victory.

Earlier in the day, the court restored his controversial travel ban against Muslim-majority countries in the Middle East.

It had been blocked in February after hysterical protests and repeated court motions who claimed it was unconstitutional.

On Monday, the Court reinstated it with the amendment that it only applies now to people with no ties to the US, meaning citizens from the affected countries who have jobs, families or other commitments in the country will be allowed to stay.

In a late-night tweet, the president said the decision was a "great day for America's future Security and Safety."

He added: "I will keep fighting for the American people, & WIN!"