DUBAI (Reuters) - The United Arab Emirates will lodge a complaint against Qatar at the United Nations’ aviation agency on Tuesday after Qatari war planes allegedly intercepted UAE civilian aircraft, a UAE official said.

The UAE said on Monday that Qatari air force jets had intercepted two UAE civilian aircraft on routine commercial flights to Bahrain. Qatar has said the claims are “completely untrue”.

The UAE will accuse Qatar of violating the Chicago Convention, which governs the use of airspace, in a complaint to the International Civil Aviation Organization (ICAO), UAE General Civil Aviation Authority Director-General Saif Mohammed al-Suwaidi told Reuters.

Suwaidi said two Qatari war planes twice flew dangerously close to the UAE airliners as they descended towards Bahrain International Airport in separate incidents on Monday, and could be seen by the pilots and passengers.

“It’s a very obvious violation,” he said by phone.

The UAE, along with Saudi Arabia, Bahrain and Egypt, has imposed travel, diplomatic and trade sanctions on Qatar since last June, accusing it of supporting terrorism.

Qatar denies the charge and has accused the four countries of trying to make it conform to their foreign policy positions.

Suwaidi said the UAE aircraft had been intercepted in air space managed by Bahrain. He declined to say whether their flight paths had taken them across Qatar, the most common route from the UAE to Bahrain.

The UAE has banned Qatari aircraft from using its airspace as part of the restrictions imposed since June. Qatar has not reciprocated .

Suwaidi said that Bahraini radar had determined the fighter jets originated and returned from Doha, and pilots of the UAE commercial planes had identified the aircraft as Mirage war planes, which are used by several Arab air forces, including Qatar’s.

Suwaidi declined to say which airlines had been intercepted. Bahrain’s state news agency BNA earlier reported that they were Emirates and Etihad flights, though gave a flight number for Etihad flight that does not exist. Emirates and Etihad declined to comment.

Suwaidi said he was confident that ICAO could stop Qatar from repeating Monday’s incidents but that the UAE could consider to re-routing its flights as a precautionary step.

Changing flight paths can be costly for airlines if it means flying longer routes and subsequently using more fuel, often their biggest single operating expense.

Asked if the UAE would consider escorting civilian aircraft, Suwaidi that the UAE could “use different tools to protect its airlines.” He did not elaborate.