Gulf rivals Qatar and the United Arab Emirates (UAE) traded accusations on Friday over a complaint by Doha that an Emirati fighter jet had violated its airspace.

Qatar, which has faced a boycott by Arab states including the UAE since last June, said it had lodged a protest at the United Nations about the violation which allegedly took place on December 21.

The Qatari foreign ministry said on its Twitter account that it informed the UN secretary general and the president of the Security Council that the UAE jet “flew over the exclusive economic zone of Qatar” for one minute.

The ministry said that "the UAE plane entered the airspace of the State of Qatar without prior knowledge or approval of the competent Qatari authorities.”

It called the incident “a flagrant violation of the sovereignty and territorial integrity of the State of Qatar, as well as a flagrant violation of the provisions of international law, conventions, charters and international norms.”

The UAE quickly denied the accusation. “The Qatari complaint about the Emirati violation of its airspace is untrue and confused,” UAE Minister of State for Foreign Affairs Anwar Gargash said on Twitter.

“We are working to respond officially to it with evidence and proof. What we see is an escalation and unjustified,” he said.

“What has been happening under the table is now taking place in the open,” he added.

Tensions have escalated in the Gulf since Saudi Arabia, the UAE, Bahrain and Egypt cut all ties with Qatar in June, largely isolating the emirate in the oil-rich Gulf.

The four countries accuse Doha of supporting extremists and being too close to Iran, Saudi Arabia's arch-rival. They have banned all flights to and from Doha and cut off most trade links.

Qatar denies the allegations, arguing the bloc aims to incite regime change in Doha.