The blame game, which includes the detention of at least one senior Russian intelligence official, doesn’t appear to pose any immediate threat to Russian President Vladimir Putin’s iron grip on power, but the U.S. officials are watching the machinations closely.

A U.S. official described as credible reports that the commander of the FSB intelligence agency’s unit responsible for Ukraine had been placed under house arrest.

The official, in an interview, also said bickering had broken out between the FSB and the Russian Ministry of Defense, two of the principal government units responsible for the preparation of the Feb. 24 invasion…

Current and former U.S. officials say Russian intelligence agencies often shy away from telling their bosses bad news and may have reinforced Mr. Putin’s views, which he has expressed publicly, that Ukraine was a dysfunctional country whose leadership would rapidly collapse as some of its citizens welcomed Russian troops.