Russia and the US seem to be edging closer to war over the Syrian chemical weapons attack

The US accused Russia of having known about and trying to cover up the April 7 chemical weapons attack that killed 87 in Syria, while the Russia threatened "real war" with the US and its allies if the US sanctions Russia over its ties to Syria's Assad regime on Monday.

The Associated Press reported on Monday that US officials said a Russian-made fighter jet bombed the hospital where victims of the attack sought treatment in Syria's Idlib province in what American officials believe was an attempt to cover up the usage of chemical weapons.

So far, it's unclear what actions the US may take towards Russia if it believes Russia was complicit in Syria's usage of chemical weapons.

But before that accusation, Russia had already suggested that G7 nations, which include the France, Canada, the UK, and Japan, had delivered an "ultimatum" involving increasing sanctions on Moscow that could result in "real war" between the US, their allies, and Russia.

Experts have told Business Insider that while the US and EU have sanctions on the books punishing Moscow for its actions in Ukraine, additional sanctions targeting Russia's energy exports could potentially cripple the military powerhouse.

Additionally, Russia warned that more US strikes on Syria would be met with force.

"What America waged in an aggression on Syria is a crossing of red lines," Russia's foreign ministry said in a statement. "From now on we will respond with force to any aggressor or any breach of red lines from whoever it is and America knows our ability to respond well."

Russia and Syria have both denied culpability in the chemical weapon attack on April 4, saying that instead their jets bombed a rebel base that contained the "toxic substances" which killed nearby civilians.

But experts say that the components for sarin gas, which they believe was used in the attack, are stored separately, and the Russian/Syrian explanation does not stand up to scrutiny.

After the US retaliated towards Syria with 59 cruise missiles fired at an airfield, Russia reportedly suspended key military agreements with the US that reduce the risk of war by coordinating air traffic in Syria's congested airspace and keeping open a deconflicting channel, where incidents can be discussed before militaries escalate the situation.

However, Secretary of State Rex Tillerson told CBS' "Face the Nation" that "as far as I know, the line of communication continues to be open," and that "the battlefield commanders are able to communicate with one another."

US and Syrian airstrikes and traffic over Syria have also continued at a regular pace, with the US bombing ISIS targets near Raqqa, Syria, and Syrian warplanes taking off less than 24 hours after the US hit their Sharyat airfield.