Russia is providing Iran with intelligence to help target U.S. forces in the Middle East, according to three officials familiar with the matter.

The assistance suggests the rapidly expanding war now includes the involvement of one of Washington’s key nuclear-armed rivals with advanced intelligence capabilities, The Caspian Post reports, citing The Washington Post.

Since the conflict began on Saturday, Russia has reportedly shared the locations of U.S. military assets with Iran, including warships and aircraft, the officials said. They spoke on condition of anonymity because of the sensitivity of the issue.

The Russian Embassy in Washington did not respond to requests for comment.

Moscow has previously called for an end to the war, describing it as an “unprovoked act of armed aggression.”

Officials said the exact scope of Russia’s targeting assistance remains unclear. They added that Iran’s own capability to locate U.S. forces has been degraded less than a week into the fighting.

The conflict has already caused casualties. Six U.S. troops were killed and several others injured in an Iranian drone attack on Sunday in Kuwait. Iran has launched thousands of one-way attack drones and hundreds of missiles at U.S. military sites, embassies and civilian areas.

Meanwhile, the joint U.S.-Israeli campaign has struck more than 2,000 Iranian targets, including ballistic missile facilities, naval assets and locations linked to the country’s leadership.

“The Iranian regime is being absolutely crushed,” White House spokeswoman Anna Kelly said, without addressing the reports of Russian assistance. “Their ballistic missile retaliation is decreasing every day, their navy is being wiped out, their production capacity is being demolished, and proxies are hardly putting up a fight.”

The CIA and the Pentagon declined to comment on the reports.

Two officials familiar with the intelligence assessment said China does not appear to be providing military assistance to Iran despite close relations between the two countries.

Analysts noted that intelligence sharing could help explain Iran’s strikes on U.S. military infrastructure, including command and control facilities, radar systems and temporary structures. One such attack in Kuwait killed six American service members.

In recent days, the CIA station at the U.S. Embassy in Riyadh, Saudi Arabia’s capital, was also struck.