A Syrian man wears an oxygen mask at a make-shift hospital following a reported gas attack on the rebel-held besieged town of Douma in the eastern Ghouta region on the outskirts of the capital Damascus on January 22, 2018. (AFP PHOTO)

MOSCOW, Jan. 25 (Xinhua) -- Moscow deems the U.S. accusations that Russia or the Syrian government was responsible for a toxic gas attack in the Eastern Ghouta suburb of Damascus earlier this week as unfounded slander, the Russia Foreign Ministry has said.

"Essentially, a massive propaganda attack was undertaken to blacken Russia on the world arena and undermine efforts for a peaceful settlement in Syria," it said in a statement published Wednesday.

On Tuesday, a number of high-ranking U.S. officials accused Moscow and Damascus of organizing the toxic chlorine gas attack on Monday. The White Helmets civil defense rescue force reported that 13 civilians were injured in the incident.

The Russian ministry stressed that there had been no proof of the attack, other than the report by the "notorious White Helmets, which have long collaborated with terrorist groups and completely discredited themselves by provocations and the constant spread of outright lies."

The United States accused Russia of unwillingness to investigate incidents with toxic substances in Syria, although the United States itself obstructed an objective investigation, said the ministry.

The United States and its allies have been constantly blocking the Russian proposal to adopt a United Nations Security Council resolution or a statement of its chairman condemning the acts of chemical terrorism in the Middle East, where militants not only use toxic chemicals, but also acquired capabilities to make warfare agents by themselves, said the ministry.

"We advise Washington to ponder, where its path of scrapping relations with Russia could lead and whether this meets the interests of the American people," said the ministry.