Under U.S. President Donald Trump, the level of trust between the U.S. and Russia has deteriorated, Russian President Putin said Tuesday as his country's foreign minister met his American counterpart.

>> Analysis: Trump's comprehensive demolition of Putin propaganda trying to cover up Assad's chemical attack <<

Russia's Foreign Minister Sergei Lavrov said at a meeting with U.S. Secretary of State Rex Tillerson in Moscow on Wednesday that it was important not to allow a repeat of U.S. strikes in Syria.

Open gallery view Russian Foreign Minister Sergei Lavrov and U.S. Secretary of State Rex Tillerson enter a hall during their meeting in Moscow, Russia, April 12, 2017. Credit: MAXIM SHEMETOV/REUTERS

Lavrov said the strikes carried out by the United States on a Syrian airbase last week were unlawful.

>> Three scenarios to expect from Tillerson-Putin clash of the titans | Analysis <<

He added that he expected to hold frank and honest discussions with Tillerson on forming a broad anti-terrorism coalition.

On Tuesday, the White House accused Russia of taking part in a cover-up of the chemical weapons attack in Syria.

According to a declassified report released Tuesday, U.S. intelligence confirms that the Syrian regime used sarin gas on civilians, and that the Syrian and Russian governments are seeking to confuse the international community by disseminating "false narratives."

The U.S. position on Syria remains a mystery to Moscow and Washington's rhetoric tends to be primitive and loutish, Russian news agencies quoted Deputy Foreign Minister Sergei Ryabkov as saying on Wednesday.

Ryabkov's remarks were released minutes before U.S. Secretary of State Rex Tillerson, the highest level representative of the Trump administration to visit Russia, was due to start talks with his Russian counterpart.

As Tillerson arrived in Moscow, President Donald Trump declared Assad "an animal."

"Frankly, Putin is backing a person that's truly an evil person. I think it's very bad for Russia," Trump told the Fox Business Network. "I think it's very bad for mankind."

Ryabkov said that at the talks Russia expected to discuss no-fly zones in Syria, and that North Korea and Ukraine would also be on the agenda.

"As a whole, the administration's stance with regard to Syria remains a mystery. Inconsistency is what comes to mind first of all," RIA news agency quoted Rybakov as telling reporters.

"In general, primitiveness and loutishness are very characteristic of the current rhetoric coming out of Washington. We'll hope that this doesn't become the substance of American policy," RIA quoted Ryabkov as saying.