Trump on Monday warned Syrian President Bashar al-Assad and his allies Iran and Russia not to "recklessly attack" the northwestern Syrian province.
"Just to speak out with some warnings, without taking into account the very dangerous, negative potential for the whole situation in Syria, is probably not a full, comprehensive approach," Kremlin spokesman Dmitry Peskov said.
The presence of terrorist in Idlib was undermining the Syrian peace process and making the region a base for attacks on Russian forces in Syria, Peskov added.
"A fairly large group of terrorists has settled there and of course this leads to a general destabilization of the situation. It undermines attempts to bring the situation onto the track of a political-diplomatic settlement," he said.
"We know that Syria's armed forces are preparing to resolve this problem," he added.
Russia resumed airstrikes against terrorist in Idlib province on Tuesday after a hiatus of several weeks, according to a war monitor.
The situation around Idlib will be one of the main items on the agenda when the presidents of Russia, Iran and Turkey meet in Tehran this week, Peskov told reporters on a conference call, declining to elaborate further.
Syrian government forces are now massing around the northwestern province of Idlib, which is held by a complex array of militants, many of whom have been blacklisted as "terrorists" by world powers.
Russia and Iran have insisted that terror groups in Idlib must be defeated and are expected to back government forces in any assault.
Since early 2017, Iran, Russia and Turkey have sponsored a negotiations track based in the Kazakh capital to tamp down hostilities in Syria.
Last year, they had designated Idlib as a "de-escalation" zone where violence would halt in preparation for a countrywide cease-fire.
Despite Trump's warning, analysts believe the United States appears resigned to the likelihood of a final military victory by Syrian government forces.
Trump said in April that "it's time" to bring American troops home from Syria – once the terrorists of the Daesh terror group had been definitively defeated.
While he quickly backed away from talk of an immediate withdrawal, his underlying determination to leave Syria's seven-year war as soon as possible seems unchanged.
Reuters and AFP contributed to this story.