US authorities have blocked the websites of several major Iranian state-linked news outlets accused of spreading disinformation, the Department of Justice said Tuesday.

"Today, pursuant to court orders, the United States seized 33 websites used by the Iranian Islamic Radio and Television Union (IRTVU) and three websites operated by Kata'ib Hizballah (KH), in violation of US sanctions," the department said in a statement.

Several of the sites were back online within hours with new domain addresses.

KH, also spelled Kataib Hezbollah, is an Iran-aligned Iraqi militia group that has been designated a terrorist organization by the US.

Which sites were affected? 

The websites of Press TV and Iranian Arabic news service Al-Alam only showed a single page with the statement: "This website has been seized."

The pages displayed logos of the FBI and the Department of Commerce and referenced US sanctions laws.

However, both later came back online using Iranian domain addresses Alalam.ir and Presstv.ir.

The Yemeni Houthi rebels-linked Al-Masirah website was also seized, along with the web domain of Tehran-based Arabic-language channel Al-Kawthar TV.

Lualua TV, an Arabic-language Bahraini independent channel that broadcasts from Britain was also reportedly affected.

The Department of Justice last year shut down nearly 100 websites tied to Iran's Revolutionary Guard for spreading disinformation.

How did Iran respond?

Islamic Republic of Iran Broadcasting (IRIB), the owner of Press TV and Al-Alam, accused the US of stifling freedom of expression.

The IRIB said the US had teamed up with Israel and Saudi Arabia "to block pro-resistance media outlets exposing the crimes of US allies in the region."

Press TV, the Iranian government's main English-language satellite TV channel, has garnered controversy in the past for promoting antisemitic conspiracy theories and Holocaust denial. The station has lost its license to broadcast on UK airwaves.

The move by the US to shut down the outlets comes amid heightened tensions between the two countries, and after Iran elected a new president. Hardliner Ebrahim Raisi has refused to meet with US President Joe Biden or scale back Tehran's ballistic missile program.