US President Donald Trump has accused the Syrian government of launching a chemical attack near the capital Damascus, saying there is a “big price to pay” by Syrian President, Bashar al-Assad.

Trump’s baseless accusations were made on Sunday on Twitter after the Syrian government strongly rejected using chemical weapons. Russia also described the latest allegations against Syria as “bogus.”

Trump also blamed Russian President Vladimir Putin and Iran for the alleged attack.

"President Putin, Russia and Iran are responsible for backing animal Assad. Big price to pay," Trump said in a pair of tweets.  He added:  "Many dead, including women and children, in mindless CHEMICAL attack in Syria. Area of atrocity is in lockdown and encircled by Syrian Army, making it completely inaccessible to outside world".

The alleged chemical attack on Saturday in the militant-held town of Douma in Eastern Ghouta region, drew international condemnation from various countries and international bodies.

Eastern Ghouta, which is home to nearly 400,000 people, fell to multiple militant groups in 2012, months after Syria plunged into crisis and has since served as a launch pad for fatal attacks against residents and infrastructure in Damascus.

Damascus, in a statement released late on Saturday, strongly rejected the allegation of using chemical munitions and said that the so-called Jaish al-Islam Takfiri terrorist group, which has dominant presence in Douma, was repeating the accusations “in order to accuse the Syrian Arab army, in a blatant attempt to hinder the Army’s advance.”

On Sunday, the US State Department also issued a strongly-worded statement, blaming the Syrian government for allegedly conducting the attack. It further said that Moscow was “ultimately bearing responsibility” for all chemical incidents in the Arab country, regardless of who carried them out.

One of Trump's top homeland security advisers said on Sunday the Unites States will not rule out launching a missile attack in response to the alleged chemical attack. "I wouldn't take anything off the table," White House Homeland Security and Counterterrorism Adviser Thomas Bossert said in an interview on ABC's "This Week."

The head of the United Nations said on Sunday he was "particularly alarmed" by the accusations. Secretary-General Antonio Guterres said in a statement that he was "deeply concerned" about renewed violence in the city of Douma.

Syria surrendered its stockpiles of chemical weapons in 2014 to a joint mission led by the US and the Organization for the Prohibition of Chemical Weapons (OPCW), which oversaw the destruction of the stockpiles.