Sergei Lavrov has stressed "the unacceptability of the actions of the US authorities, who have arrested Russian citizen Maria Butina in the United States on the basis of fabricated charges, and the need for her early release," the Russian Foreign Ministry said in a statement.

Russian Foreign Minister Sergei Lavrov and US Secretary of State Mike Pompeo have held a telephone conversation at the US side’s request.

"The minister and the secretary of state also discussed the situation in and around Syria, including the possible interaction of Russia and the United States with other countries to address humanitarian problems in Syria and the tasks associated with supporting the efforts to promote the denuclearization of the Korean peninsula," the commentary on the Russian Foreign Ministry’s website read.

According to the ministry, "following the Russian-American summit in Helsinki on July 16, the foreign ministers exchanged views on the prospects for further developing relations between our countries with a view to their normalization on an equal and mutually beneficial basis."

On July 15, US authorities arrested Butina, 29, and charged her with both conspiracy to act and acting as a spy and foreign agent. Despite denying the accusations, the Russian citizen faces up to 15 years in jail.