A senior UAE official said on Monday that worldwide monitoring was needed in the standoff between Qatar and its Arab neighbors, adding he saw signs that the pressure exerted on Doha "was working".
Officials, quoted under the condition of anonymity, have said it is unclear whether Abu Dhabi broke the servers or just paid for their crackdown.
The United Arab Emirates reportedly was behind the hacking of Qatari websites in late May which led to boycotting of the nation by Saudi-led group of countries.
The four Arab states accuse Qatar of ties to Iran and of funding Islamist extremist groups.
A statement by the Qatar government said that it believed the Post report to be true, while the UAE denied the allegations. The hack also involved the planting of damning false stories about Qatar's emir.
UAE Minister of State for Foreign Affairs Anwar bin Mohammed Gargash said Monday that the Washington Post report was false. "Inciting violence, encouraging radicalization and undermining the stability of its neighbors".
"We've said before that we are not going to escalate but we will take, here and there, measures that we need to take within our sovereign rights and within worldwide law", he said.
The agreement between Doha and Washington was struck during U.S. secretary of state Rex Tillerson's four-day mediation mission to try and end the rift between Qatar and its neighbours.
Doha rejected the demands, saying they would undermine its sovereignty.
In early July, the Arab states sent a list of demand and required Doha to cut diplomatic relations with Iran, close the Turkish military base, eliminate Al-Jazeera TV channel, extradite all persons wanted in four countries on charges of terrorism and pay compensation.
Saudi Arabia and its allies have not said what steps they could take next, but there are fears of a wider embargo that would hurt the Qatari economy, with credit ratings agency Moody's announcing it was changing Qatar's outlook to negative over the crisis.