"The assassination of Quds Force Commander, Lieutenant General Qassem Soleimani, had "crossed all the red lines" and constituted a "dangerous escalation" that would "change the features of the regional conflict, which has dominated the region thus far," Lebanese media quoted Berri as saying.

Lieutenant General Soleimani who was the Islamic Revolution Guard Corps' (IRGC) Quds Force commander was assassinated by the US with the acting Commander of the Iraqi Popular Mobilization Units (PMU), known as the Hashd al-Shaabi, Abu Mahdi Al-Mohandes, and eight other military forces with record of fighting the Daesh (ISIS) in Iraq.

The Supreme Leader has called for proportionate military action against the US interests in response to the heinous crime against the Iranian Commander on a diplomatic mission to Baghdad.

Iran’s Islamic Revolution Guard Corps (IRGC) targeted the US airbase of Ain al-Assad in Al-Anbar province in western Iraq on Wednesday.

The IRGC said in a statement that it would release more details about the strike.

Iran's Supreme Leader Ayatollah Seyyed Ali Khamenei commented on the martyrdom of the great commander of the IRGC's Quds Forces and said harsh and severe revenge is awaiting the criminals.

Earlier, Iran's Ambassador and Permanent Representative to the UN Majid Takht Ravanchi in a letter to the UN Secretary-General António Guterres underlined Iran right to self-defense against any threat.

"In conformity with international law and in exercising its inherent right to self-defense, Iran will take all necessary and proportionate measures against any threat or use of force," Takht Ravanchi said in his letter.