Iran is weighing options to retaliate in the wake of the killing of its top military commander Gen. Qasem Soleimani in a U.S. airstrike near Baghdad airport Friday. 

Soleimani, who headed the Islamic Revolutionary Guards Corps' (IRGC) Quds Force, was killed alongside close aides, including the deputy head of Iraq’s Popular Mobilization Force (PMF), Abu Mahdi al-Muhandis.

His killing sent shockwaves across the region, putting Iran and the U.S. on the brink of war, again. Iran vowed ‘severe retaliation’ for Soleimani’s killing.

According to reports, the drone strike that targeted the cavalcade of Soleimani and his associates was ordered by U.S. President Donald Trump.

The U.S. accused Soleimani and Muhandis of planning attacks against U.S. service members and facilities in Iraq and the region.

Iranian Parliament Speaker Ali Larijani rejected the Trump claims as “lies.”

Scenarios of retaliation

After Iranian Supreme Leader Ayatollah Khamenei’s threat of “hard revenge” started echoing in the political corridors of Iran, the Supreme National Security Council (SNSC) also vowed a “strong response” to Soleimani killing and his associates.

“The regime of the United States will be responsible for all the consequences of this criminal adventurism,” the Council said in its statement Friday. “The U.S. should know that the criminal attack against Gen. Soleimani was its biggest strategic mistake in West Asia and it will not easily get away with the consequences of this miscalculation.”

As Soleimani’s funeral was taking place Tuesday in his hometown of Kerman in southern Iran, Ali Shamkhani, the secretary of SNSC, said at least 13 scenarios for “revenge” have been discussed in the Council meetings.

“If all Council members agree even on the weakest scenario, it will bring a historic nightmare for America,” said the top security official in Iran, as quoted by a local news agency.

Without divulging details about the “revenge operation” against the U.S., he said it will “not be just one single operation,” suggesting Iran is looking to strike at multiple sites.

“The U.S. knows they are vulnerable to Iran's reaction. That's why a number of their patrols have reduced and forces are mainly concentrated at bases,” he said, adding that the U.S. is aware of Iran’s long-range power.

“The response is likely to be triggered by medium-range and long-range missiles,” he asserted, without giving more details.

Shamkhani said the response will be directed at the U.S. forces in the region, if they do not immediately vacate bases in Iran’s neighboring countries. “If the forces want to take shelter in the bases, we will destroy the bases in addition to the forces,” he warned.

The official said there are 19 U.S. military bases in the region, including 11 head bases located in the east and west of Iranian border and eight in the north and south of Iranian border.

Iran, he reiterated, is aware of their military equipment and is monitoring the smallest developments.

''If American forces do not leave our region on their foot and vertically, we will do something that their dead bodies go horizontally,'' he warned.

U.S. President Donald Trump warned Friday that if Iran attacks any American base or soldier, the U.S. will likely retaliate. “The United States just spent two trillion dollars on military equipment. We are the biggest and by far the best in the world,” he tweeted.