The Kremlin said Sunday that the U.S. Central Intelligence Agency provided Russian authorities with information that thwarted a series of Islamic State bombings planned in St. Petersburg.
Moscow said Russian President Vladimir Putin called U.S. President Donald Trump to thank him for the CIA information, a call the White House confirmed.
Russia said the intelligence was significant enough for its Federal Security Service to track down seven suspects last week who were planning suicide bomb attacks Saturday on the two-century-old Kazan Cathedral and other sites in Russia's second largest city. Three more were arrested Sunday who authorities said were linked to the planned attack.
Authorities said they confiscated a large number of explosives used to make homemade bombs, automatic rifles, munitions and extremist literature.
Law enforcement agencies said the suspects had been using the messaging app Telegram to communicate with Islamic State leaders outside Russia. In October, a Russian court fined Telegram $14,000 for refusing to provide security officials with information about an April attack on St. Petersburg's subway that killed 16 people and injured more than 50.
The state news agency RIA Novosti broadcast a video showing a man identified as Yevgeny Yefimov confessing that he planned to carry out Saturday's St. Petersburg attack.
"My job was to make explosives, put it in bottles and attach pieces of shrapnel,'' Yefimov said in the video.
Later, Yefimov told a St. Petersburg court that the cathedral was an intended target.
Moscow said Putin asked Trump to express his gratitude to the CIA and that Russia in turn would hand over information it learns about possible terrorist attacks in the U.S., as it says it has in the past.
Sunday's call between the two leaders was their second in four days and comes at a contentious point in U.S.-Russia relations.
U.S. sanctions are still in place protesting Moscow's 2014 annexation of Ukraine's Crimean Peninsula, while the U.S. intelligence community has concluded that Russia meddled in the 2016 U.S. election to help Trump win.
Criminal and congressional investigations are underway in the U.S. about the Trump campaign's links to Moscow. Putin has often denied Russian interference and Trump has frequently disparaged the investigations as an excuse by Democrats to explain his upset victory over former U.S. Secretary of State Hillary Clinton.