Saudi Arabia criticised Qatar on Monday for rejecting the outcome of recent Mecca talks on regional tensions with Iran, while the UAE accused Doha of "backtracking" on the summits' conclusions.
Doha, which attended the three meetings in the holy city, said on Sunday it rejected the outcomes as it had not been properly consulted.
Saudi Arabia's minister of state for foreign affairs, Adel al-Jubeir, fired back. "Countries... during summits announce their positions and reservations in the meetings according to customs and not after the meetings," he said on Twitter.
Saudi Arabia hosted the three summits over the weekend critical of Iran after King Salman warned that "terrorist" attacks in the Gulf region could imperil global energy supplies.
Riyadh convened the crisis meetings after recent attacks on oil infrastructure and regional shipping, incidents which Tehran has denied any involvement in.
Qatar's foreign minister said Sunday that the concluding statements of the summits "were ready in advance and we were not consulted on them".
More From This Section
"Qatar has reservations on the Arab and Gulf summits because some of their terms are contrary to Doha's foreign policy," Mohammed bin Abdulrahman Al-Thani told the Al-Araby broadcaster.
The United Arab Emirates' minister of state for foreign affairs, Anwar Gargash, criticised Doha for being "weak" under pressure.
"Seems to me that attendance and agreement in meetings and then backtracking on what was decided on is (a result of) pressure on the weak that lack sovereignty or have ill intentions or lack credibility, and it might be all these factors," he tweeted late Sunday.
Qatar is the subject of a two-year Saudi-led economic embargo including bans on direct air, land and sea travel between the boycotting nations and Qatar, as well as sanctions.
The alliance, which also includes Bahrain, Egypt and the UAE, accuses Qatar of supporting Islamist movements and Iran -- claims it denies.
Doha has looked to Tehran to ease its economic isolation, sourcing key imports from Iran and re-routing many flights by its flag carrier Qatar Airways over the Islamic republic.