Putin calls Trump to thank him after U.S. provides Russia with intelligence that helped it thwart attack in St. Petersburg.

The United States provided intelligence to Russia that helped it thwart a potentially deadly bomb attack in St. Petersburg, U.S. and Russian officials said on Sunday, according to Reuters.

Russian President Vladimir Putin telephoned U.S. President Donald Trump on Sunday to thank him for the tip-off, which the Kremlin said helped prevent a bomb attack on a cathedral in the Russian city, as well as other sites, the report said.

The White House did not disclose details about the plot itself, but did say in the statement the attack "could have killed large numbers of people."

“President Vladimir V. Putin of Russia called President Donald J. Trump today to thank him for the advanced warning the United States intelligence agencies provided to Russia concerning a major terror plot in Saint Petersburg, Russia,” the White House said in a statement.

“Based on the information the United States provided, Russian authorities were able to capture the terrorists just prior to an attack that could have killed large numbers of people. No Russian lives were lost and the terrorist attackers were caught and are now incarcerated. President Trump appreciated the call and told President Putin that he and the entire United States intelligence community were pleased to have helped save so many lives,” it added.

Neither the Kremlin nor the White House identified the would-be attackers.

Relations between Washington and Moscow have been damaged by disagreements over the wars in Ukraine and Syria, although Trump pledged during his election campaign to pursue better ties with Moscow.

That has been complicated by U.S. allegations - denied by Russia - that the Kremlin meddled in last year's U.S. presidential election to help Trump win.

The phone call on Sunday between Trump and Putin was at least the second such call in the past week. On Thursday, Putin and Trump discussed the crisis in North Korea.

According to the Kremlin statement, the foiled attack was to have been carried out on Kazansky Cathedral, in Russia's second city of St. Petersburg, and on other locations in the city where large numbers of people gather. The cathedral is a popular tourist site.

Russian media reported last week that the Federal Security Service had detained followers of the Islamic State (ISIS) group who had been planning a suicide bomb attack on Kazansky Cathedral on Saturday.

Putin said Russia would alert U.S. authorities if it received information about any attack being planned on the United States, the Kremlin said.

Russia has been targeted by several Islamist attacks, including an attack in April that killed 14 people when an explosion tore through a train carriage in a metro tunnel in St. Petersburg.

That attack was claimed by the Imam Shamil Battalion, a little-known group claiming to have links to Al-Qaeda.

In August, Russian security forces foiled an ISIS terror plot that was slated for September 1 on the first day of school.