Bahrain said on Tuesday that radar tracks showed Qatari fighter jets passing by Emirati commercial airliners on their way to the island nation, encounters which started a new dispute between the Gulf nations amid the diplomatic crisis gripping Doha.

The two alleged fly-bys on Monday morning could further escalate tensions between Qatar and the four Arab nations that have been boycotting it for months, among them the UAE, home to the world's busiest international airport. They also could affect long-haul airline travel, as the region's carriers are a crucial link between the East and West.

Emirati officials on Monday described the fly-bys as though the fighter jets "intercepted" their civilian aircraft. Qatari officials deny their jets intercepted the aircraft and on Tuesday dismissed the footage as "unauthenticated videos."

Bahrain state television aired radar footage the broadcaster described as showing Emirates flight No. EK837 from Dubai flying toward Bahrain International Airport at 3,170 meters (10,400 feet). Two other radar signals the broadcaster described as Qatari fighter jets flew at around 2,590 meters (8,500 feet) in front of the Emirates flight. The radar screen briefly flashes orange text, likely a collision warning.

It wasn't clear from the footage at what distance the fighter jets allegedly passed the Emirates flight, but Bahrain previously described the distance as being 3.2 kilometers (2 miles).

The broadcaster also aired footage of an aeronautical chart it said showed a Qatari fighter jet flying across the flight path of a just-passed Etihad airliner, both at 24,000 meters (8,000 feet). It identified the flight as ETD23B, which corresponds to Flight No. EY371, a direct Abu Dhabi-Bahrain flight that took off Monday morning.

Both Dubai-based Emirates and Abu Dhabi-based Etihad have declined to comment. Both flights flew in international waters just north of the tip of Qatar, a peninsular nation that juts into the Arabian Gulf, before landing in nearby Bahrain.

The UAE's state-run WAM news agency on Monday quoted Saif al-Suwaidi, the director-general of its civil aviation division, as saying crew and passengers onboard the flights saw the military aircraft.

It "constituted a clear and explicit threat to the lives of innocent civilians," he said.

Reached on Tuesday, Qatar's Government Communication Office dismissed the Bahrain state television report as part of a "smear campaign" against it by the UAE.

"These matter should be dealt with by filing a formal complaint to the U.N. Security Council, as Qatar has done following two breaches by UAE military aircraft of the state of Qatar's airspace, and not by distributing unauthenticated videos to the media as how the blockading nations have done since the start of the crisis," it said in a statement to The Associated Press.

At issue as well is language in the dispute. Intercepts normally refer to military jets flying alongside passenger planes and giving orders in emergencies. Military jets also don't necessarily file flight plans, as required by commercial airlines.

Qatar's stock exchange dropped some 2.5 percent in trading Monday, one of its biggest jolts since the crisis began. 

Bahrain, Egypt, Saudi Arabia and the UAE cut off Qatar's land, sea and air routes on June 5 over its alleged support of extremists and close ties with Iran.

Qatar has long denied funding extremists. It recently restored full diplomatic relations with Iran, with which it shares a massive offshore natural gas field that makes the country and its 250,000 citizens extremely wealthy.

The crisis has hurt Qatar Airways, Doha's long-haul carrier that competes with Emirates and Etihad.

Qatar had complained to the Montreal-based International Civil Aviation Organization about the boycotting nations cutting off its air routes, forcing the carrier to take longer flights through Iran and Turkey. Its regional feeder flights in Saudi Arabia and the UAE also have been cut off.

However, widening the Gulf dispute to include civilian aviation and airspace could hurt Emirati airlines already stung by President Donald Trump's travel bans, as well as last year's since-lifted ban on laptops in airplane cabins. 

The White House said Trump spoke Monday with Qatar's ruling emir, Sheikh Tamim bin Hamad Al Thani, saying the president reiterated his support for unity among Gulf Arab nations. Trump also thanked Sheikh Tamim for Qatar's "action to counter terrorism and extremism," the White House said. 

Qatar earlier accused Emirati military jets of violating its air space in December and January in two incidents, filing a complaint to the United Nations. Anwar Gargash, the Emirati minister of state for foreign affairs, wrote Friday on Twitter that Qatar's airspace complaints were "incorrect and confused," without elaborating.