"At the direction of the (US) President, the US military has taken decisive defensive action to protect US personnel abroad by killing Qassem Soleimani," Efe news reported citing the statement as saying on Friday.
"The strike was aimed at deterring future Iranian attack plans... The US will continue to take all necessary action to protect our people and our interests wherever they are around the world," it added.
Following the development, President Trump posted a picture of an American flag on his Twitter account, without any comment.
In a statement issued on Friday, the IRGC said that Abu Mahdi al-Muhandis, the second-in-command of the Hashd Shaabi or the Iraqi Popular Mobilization Forces (PMF), was also killed along with Soleimani in the strike that targeted their vehicle on the Baghdad International Airport road, the Tehran-based Press TV reported.
Iranian Foreign Minister Mohammad Javad Zarif called the US attack as "extremely dangerous and a foolish escalation".
"The US' act of international terrorism, targeting and assassinating General Soleimani, the most effective force fighting IS, Al Nusrah, Al Qaeda, is extremely dangerous and a foolish escalation.
"The US bears responsibility for all consequences of its rogue adventurism," he said in a series of tweets.
Meanwhile, the PMF has also confirmed the incident, adding that its public relations director Mohammed Reza al-Jaberi and four other members were also killed after three Katyusha rockets struck a military base next to the Baghdad airport earlier on Friday.
It described the attack as a "cowardly US bombing".
Since 1998, Maj Gen Soleimani led Iran's Quds Force - the IRGC's elite unit which handles clandestine operations abroad, said the BBC.
In that position Gen Soleimani played a key role bolstering Bashar al-Assad's Iranian-supported government in the Syrian Civil War, and in the fight against the Islamic State (IS) group in Iraq.
He was a hugely significant figure in the Iranian regime. His Quds Force reported directly to Supreme Leader Ayatollah Ali Khamenei.
He first came to prominence in his country serving in the Iran-Iraq War in the 1980s.
Friday's targeted strike took place amid increased tensions between Washington and Tehran after hundreds of protesters stormed the US Embassy in Baghdad on Tuesday, where they managed to breach the main gate and enter some rooms, lighting fires.
The siege was in response to an American attack on the positions of some Iraqi militia battalions in western Iraq on December 29 in which, 25 of militiamen died and more than 50 were injured according to the PMF.
The Pentagon said at the time that it had launched "defensive attacks" against Kataib Hizbollah, which operates under the umbrella of the PMF and is allegedly responsible for launching projectiles and rockets at US interests on Iraqi soil.
Earlier on Thursday, Pentagon chief Mark Esper asked Iran to stop its attacks against the US in the Middle East and said "attacks against us will be met with responses in the time, manner, and place of our choosing".
( With inputs from IANS )