A preliminary investigation has confirmed that Qatar's state news agency was hacked and false statements attributed to the country's ruler were posted that helped spark a rift with other Gulf states, the Qatari foreign ministry said on Wednesday.

Saudi Arabia, Egypt, the United Arab Emirates, and several other countries cut their ties with Doha on Monday in part over the comments briefly posted on the Qatar News Agency.

The article quoted Qatar's Emir Tamim bin Hamad al-Thani as cautioning against confrontation with Iran as well as defending the Palestinian group Hamas and Hezbollah, a Lebanese movement allied to Tehran.

"The Ministry said the investigation team confirmed that the piracy process had used high techniques and innovative methods by exploiting an electronic gap on the website of the Qatar News Agency," the foreign ministry said in a statement.

While it did not say who it might believe carried out the hack, the ministry added its "team confirmed that the hacked file was installed last April, which was later exploited in the publication of the fabricated news on 24/5/2017, at 12:13 AM".

The ministry said findings of the probe will be disclosed in a press conference "immediately after the team have completed the entire investigation".

The Arab countries at odds with Qatar accuse it of supporting militant groups and advancing their arch-rival Iran's agenda in the region ? charges that Doha calls baseless.

Qatar's foreign ministry thanked the US Federal Bureau of Investigation (FBI) and the British National Commission for Combating Crime (NCA) for cooperating in the investigation, without elaborating further.