Saudi-owned TV channel Al Arabiya said its rival had been barred after the ruler of Qatar was reported to have described Iran as an "Islamic power" and criticized President Trump's policy towards Tehran.
The country's communications ministry said in a statement that it had begun an investigation and that authorities would hold those responsible to account.
He blamed the Islamic Republic for training terrorists and militias and said it was responsible for spreading "destruction and chaos across the region."
The disputed Qatar news agency report also described Hamas -- considered a terrorist organization by the U.S. and European Union -- as the official representative of Palestinians, according to Arabic media.
Relations between Qatar and other Gulf states cooled in 2014 over Qatar's foreign policy and its links to the Muslim Brotherhood, a political and social organization that calls for a society based on Islamic law.