Members of the so-called Five Eyes spy alliance, as well as Israeli and Saudi officials, fear the identities of foreign assets could inadvertently be shared with Moscow.

The rupture of U.S. intelligence-sharing with Ukraine, confirmed by the CIA director, involves the targeting of longer-range strikes inside Russia.

The suspension, which could cost lives by hurting Ukraine's ability to defend itself against Russian missile strikes, followed a halt this week to U.S. military aid to Kyiv.