Qatar has recalled its ambassador from Egypt following a row about air strikes on Islamic State targets in Libya.
Foreign ministry officials said it was prompted by comments made by Egypt's delegate to the Arab League, who accused Qatar of supporting terrorism.
Qatar had expressed reservations over Egypt's unilateral military action in another Arab League member state and the risk of civilian casualties.
Relations between Doha and Cairo have been strained in recent years.
The Qatari government backed President Mohammed Morsi and his Muslim Brotherhood before his overthrow by the Egyptian military in 2013.
The Qatari-owned TV network, Al Jazeera, has also been a major source of tension, with the Egyptian authorities accusing it of serving as a mouthpiece for Mr Morsi's supporters and prosecuting its journalists.
The Egyptian air force bombed Islamic State bases in Libya on Monday in retaliation for the beheading of 21 Egyptian Coptic Christians.
After a meeting in Cairo on Wednesday, the Arab League issued a statement stressing its "complete understanding" about the air strikes and supporting Egypt's call for the lifting of the UN arms embargo on the supply of weapons to the Libyan armed forces.
But Qatar's expression of reservations about the statement was criticised.
"According to our reading in Egypt to this Qatari reservation, it became clear that Qatar has revealed its position that supports terrorism," the Egyptian permanent representative to the Arab League, Tareq Adel, was quoted as saying by the Egyptian state news agency, Mena.
In a statement published by the official QNA news agency on Thursday, Qatari foreign ministry official Saad bin Ali al-Muhannadi denounced Mr Adel's statement, saying it was "against righteousness, wisdom and principles of joint Arab action".
He said the emirate's delegate to the Arab League had merely pointed out that Egypt should have consulted its neighbours before "launching a unilateral military action in another member state, a matter which might lead to harming civilians".
Mr Muhannadi said Qatar was also against the strengthening of one party in the conflict in Libya before the conclusion of UN-backed peace talks and the formation of a national unity government.
The Gulf Co-operation Council also voiced support for Qatar, saying it rejected "accusations by Egypt's permanent envoy at the Arab League".
Secretary General Abdul Latif al-Zayani said they were "unfounded, contradict reality, and ignore the sincere efforts by Qatar, as well as the Gulf Co-operation Council and Arab states, in combating terrorism and extremism at all levels".