Tehran hit back at US US annual report on terrorism, stressing that Iran has proved in practice to be the most serious and effective force to confront and fight terrorism.

Tehran hit back at US US annual report on terrorism, stressing that Iran has proved in practice to be the most serious and effective force to confront and fight terrorism.

In a statement on Saturday night,  Foreign Ministry Spokesman Hossein Jaberi Ansari dismissed Iran's renewed blacklisting by Washington as a state sponsor of terrorism charging that it was US allies including Riyadh that were the real culprits.

“While the US allies in the region are supporting Daesh  and other terrorist groups through different methods, the Islamic Republic of Iran is in the frontline of fighting terrorism in Iraq and Syria,” IRNA news agency quoted the Iranian official as saying, referring to Arabic acronym of the ISIL Takfiri group.

The Islamic Republic of Iran within its principled policy is emphasizing on its preparation to cooperate with other governments and nations as well as international organizations in the path of real and all-out confrontation with terrorism, the Iranian official said.

Ansari meanwhile,  said Washington's support for the Zionist entity despite its decades-old occupation of the Palestinian territories made it the "biggest sponsor of state terrorism".

In its latest annual report published on Thursday, the US State Department said Iran had boosted its support for Palestinian resistance groups in Gaza last year, as well as Lebanese resistance, Hezbollah which has deployed thousands of fighters to Syria in support of the Syrian governmnet.

It said Iran also "increased its assistance to Iraqi Shiite terrorist groups, including Kataib Hezbollah," according to AFP news agency.