US drone crash: A moment fraught with danger

As such, it raises a lot of questions and represents a moment fraught with danger.

The United States' National Security Council's (NSC) John Kirby says there have been other intercepts "even in recent weeks", but that this one was different.

Could it have been an accident?

"Based on the actions of the Russian pilots, it's clear that it was unsafe, unprofessional," was the verdict of the Pentagon's Press Secretary, Air Force Brigadier General Pat Ryder.

"I think the actions speak for themselves."

Does the behaviour of Russia's pilots - allegedly dumping fuel in the path of the drone and then colliding with it - represent a significant escalation?

According to the Pentagon, the whole incident lasted about 30-40 minutes.

During that time, Gen Ryder said there was no direct communication between the Russian and American militaries.

US officials say they believe the Russian Su-27 jets involved "likely" suffered some damage, indicating that a collision was not deliberate.

"I do know that the state department is raising our concerns about the incident directly with the Russian government," he added.

What, if anything, does the episode mean for the future of American drone operations over the Black Sea, and for the vital surveillance such operations provide to Ukraine?

"If the message is that they want to deter or dissuade us from flying or operating in international airspace over the Black Sea," Mr Kirby told broadcaster VOA, "then that message will fail because that is not going to happen".

Not surprisingly, Russia would like to make it as hard as possible for Ukraine's allies to carry out such work.

Washington is being tight lipped about what has happened to the drone.

After the collision, US remote pilots were forced to bring it down in the Black Sea.

Gen Ryder would not say where it landed or whether the Russian navy was trying to recover it.

Audio recordings circulating on social media seem to indicate some kind of Russian recovery operation was under way. But this has not been confirmed.

Clearly, Washington would not be happy if such sensitive surveillance technology fell into Russian hands.

For Joe Biden, determined to support Ukraine for "as long as it takes", this is a delicate moment.

It's not just Western weaponry that's helping Ukraine to withstand Russia's invasion.

It's also a vast quantity of real-time intelligence on every aspect of Russia's military operations, including the movement of vessels in the Black Sea and the launch of missiles aimed at targets across Ukraine.

From defending Ukraine's critical national infrastructure to planning its own offensive operations, Kyiv depends heavily on the steady flow of information.

For obvious reasons, US officials won't be drawn into what, if any, additional precautions its surveillance operations will now involve.

Washington wants to keep them going, but is anxious to avoid using force, and risk getting drawn into a more direct confrontation with Moscow.

-bbc