The United Arab Emirates said on Monday Qatari air force jets had twice intercepted civilian Emirati aircraft during routine flights to Bahrain, state news agency WAM reported, amid a months-old feud between the Gulf Arab states.
Qatar denied as "completely untrue" the initial interception report, but did not immediately comment on the second.
The UAE is one of four Arab countries, along with Saudi Arabia, Bahrain and Egypt, that imposed travel, diplomatic and trade sanctions on Qatar in June 2017, accusing Doha of supporting terrorism. Qatar has denied the charges.
Qatar's rivals banned Qatari aircraft from their air space though Doha did not reciprocate with a ban of its own.
The UAE Civil Aviation Authority said the two Emirati airliners encountered the jets from Qatar, which lies between the UAE and Bahrain, while en route to Bahrain. It condemned the Qatari action as "a serious and renewed breach of international conventions and the safety of civil aircraft traffic".
A Qatari official did not immediately respond to a Reuters request for comment.
Sheikh Saif Bin Ahmed al-Thani, director of Qatar's government communications office, said on his official Twitter account that the first UAE charge, made earlier on Monday, was "completely untrue".
The Bahraini state news agency BNA said the first flight was from Emirates, which is owned by the Dubai government, but gave no details on the second flight.
On Friday, Qatar filed a complaint with the United Nations about an alleged violation of its air space in December by an Emirati military aircraft. Qatari authorities said the violation on Dec. 21, which the UAE denied, lasted one minute.