The samples tested positive for chlorine gas and an unnamed nerve agent, according to the report. The officials told NBC that the Assad regime is known to have stocks of the nerve agent sarin and has previously used a mixture of chlorine and sarin in attacks.
The officials said they were "confident" in the intelligence, though not 100 percent sure, according to NBC.
Russia and Syria have denied any involvement in the alleged attack, however officials said the U.S. has compiled intelligence that indicates the Syrian government's involvement.
President Donald Trump condemned the attack after its occurrence, calling it "atrocious." He said on Monday that he plans to make "major decisions" following the attack and will not rule out military action. Trump has not confirmed when or if the attack will take place, stating in a tweet that it "could be very soon or not so soon at all."
The chemical attack is the latest in an escalating and deadly war in Syria that has garnered global attention and worry.
The White House did not immediately respond to CNBC's request for comment on NBC's report.