Daily US Times: After the US killed the country’s most famous and important general by an airstrike on Thursday, Iranian supreme leader, Ali Khamenei, vowed to exact “severe revenge”. But former intelligence officials familiar with the region said Iran has to walk a fine line to respond strongly without provoking a war with the United States.

Qassem Soleimani was killed when a U.S. missile struck his vehicle near Baghdad International Airport. The attack also killed Abu Mahdi al-Muhandis, the leader of the Iraqi Shiite militia group Kataib Hezbollah, along with several other Quds Force and militia members.

Soleimani was a charismatic leader who for 20 years had played a key role in changing Iran’s landscape in the Middle East, particularly with regard to its use of proxy militia forces such as Lebanese Hezbollah, numerous Iraqi Shiite armed groups and the Houthi militia in Yemen.

He directed the killing of more than 600 US troops during the Iraq war using a lethal sort of roadside bomb called an explosively formed penetrator. Recentlycommanded Iran’s military efforts to shore up its ally Bashar Assad in the Syrian war and the US accused him of plotting the attack of the country’s Baghdad embassy.

A former senior CIA operations official Marc Polymeropoulos described Soleimani as ”the most famous intel figure on the planet”.

Norman Roule, the national intelligence manager for Iran until 2017 said Iran has to act very carefully now. Because of Soleimani’s iconic stature, Iran has to strike back itself, rather than by its proxies.

”But Iran must do so with enough implausible deniability to avoid giving the United States an excuse to launch a war that could lead to the collapse of the Islamic Republic. Iran will also want to avoid antagonizing Europe, China or Russia in its response”, he added.

According to Roule, Iran’s proxies will want to show their loyalty to Iran, but the way the US killed Soleimani and other associates, they will be wondering how quickly Washington will be able to locate and kill them following any attack on U.S. interests.