If you were under the impression that relations between Qatar and the Saudi-led bloc that cut diplomatic ties with the filthy-rich sheikdom last summer were set to thaw, you might want to rethink that assumption because, on Monday, Qatar fighter jets intercepted a U.A.E. plane on a regular flight to Bahrain’s capital.

Or at least according to the U.A.E’s General Civil Aviation Authority which says “it received a complaint from one of the UAE’s national carriers that one of its aircraft on a flight to Manama on a normal route had been intercepted by Qatari fighters”.

The plane was flying on usual path, the U.A.E. added, before calling the move “a flagrant [and] a serious threat to aviation safety” and a “violation to international law.” Here’s Bahrain’s statement:

• BAHRAIN SAYS QATAR JETS INTERCEPTED EMIRATES FLIGHT 837

Subsequently, the U.A.E. claimed a second airliner had been intercepted:

• U.A.E. SAYS QATAR JETS INTERCEPT ANOTHER COMMERCIAL FLIGHT: WAM

This comes just days after Qatar accused a U.A.E. fighter jet of violating its airspace. That alleged violation prompted Qatar’s UN envoy to declare that Doha would take “necessary measures” to defend its borders and airspace.

Obviously, there’s a connection between that and today’s incident.

Needless to say, Monday’s news did not go over well with Qatari stocks, which quickly erased gains on the way to diving more than 2%:

That would be the biggest drop since the blockade began and comes just five days after the QE broke above its 200-day moving average for the first time since April.

For its part, Qatar is denying the allegations:

• QATAR DENIES INTERCEPTING U.A.E. CIVILIAN PLANE: JAZEERA TV

Here’s Sheikh Saif Al Thani, head of the Qatari government communications office, calling this “completely untrue”:

The State of Qatar announces that claims that Qatari fighter jets intercepting an Emirati civilian aircraft is completely untrue. A detailed statement will follow.

— سيف بن أحمد آل ثاني (@saifaalthani) January 15, 2018

Stay tuned, because this has the potential to get interesting.