The emir, Sheikh Tamim bin Hamad al-Thani, had been quoted in May as praising Hamas and saying that Iran was an "Islamic power," the Post reported. In response, Saudi Arabia, the UAE, Egypt and Bahrain cut diplomatic and transport ties with Qatar on June 5, accusing it of supporting terrorism.
Qatar said in late May that hackers had posted fake remarks by the emir, an explanation rejected by [Persiann] Gulf states.
The Post reported that U.S. intelligence officials learned last week of newly analyzed information that showed that top UAE government officials discussed the planned hacks on May 23, the day before they occurred.
The officials said it was unclear if the UAE hacked the websites or paid for them to be carried out, the newspaper reported. The Post did not identify the intelligence officials it spoke to for the report.
UAE Ambassador Yousef al-Otaiba denied the report in a statement, saying it was "false," the Post said.
"What is true is Qatar´s behavior. Funding, supporting, and enabling extremists from the Taliban to Hamas and Qadafi. Inciting violence, encouraging radicalization, and undermining the stability of its neighbors," the statement said.
The U.S. State Department declined comment in response to a Reuters query.
The Federal Bureau of Investigation was previously known to be working with Qatar to probe the hacking.