Democratic presidential candidate, Senator Cory Booker, has expressed concern over the killing of Iranian general Qasem Soleimani at Baghdad airport. 

President Donald Trump said just two days earlier that he doesn't want a war with Iran. And while Booker agrees that Soleimani was responsible for hundreds of American deaths, he says that the airstrike may have been premature.

"This is not something that should be done on impulse," Booker said. "It should be done in a larger strategic vision and understanding what the consequences could be in taking out this significant—assassinating someone of such a significant leadership role in Iran."

"This Middle East we have seen is not going to be solved, as we know in Afghanistan now with the Afghan papers coming out, we are not going to solve these problems, as our own generals are saying, with our United States military," Booker continued. "There must be diplomatic solutions."

According to the Pentagon, Soleimani was developing plans to attack Americans in the region, but, as the airstrike was carried out without congressional approval.

"I have a lot of concerns right now as this is unfolding about that standard of the use of military force and I have a lot of concerns about a president who's already shown to have no strategy for the larger challenges we have in the Middle East, especially around Iran," Booker told CNN.

He also told MSNBC, "These are statements coming from the Trump White House. There's a lot more facts that have to come out to see if indeed this president, who already has done things that have undermined what people on both sides of the political aisle in the Senate have said do not constitute the authorization for the use of military force."