National security adviser Jake Sullivan has said that the United States will take “further action” following the country’s retaliatory airstrikes this weekend in multiple Middle Eastern countries — a move that could possibly result in a broader regional conflict.

In the past few days, the U.S. has launched strikes in Iraq, Syria and Yemen in what officials say is an effort to target Iran-backed militias. The strikes are in retaliation for a recent drone attack by militants that killed three American military personnel in Jordan – the first attack to result in U.S. combat deaths from such militias since the violence between Israel and Hamas escalated on Oct. 7.

“From our perspective, each action that we take is targeted at reducing the capabilities of the militias to be able to continue to conduct attacks against us and to send a clear message that the United States will respond when our forces are attacked, and we will respond with strength in a sustained way when American casualties are incurred,” Sullivan told Dana Bash on CNN’s “State of the Union” on Sunday.

The adviser did not directly answer Bash’s question on how he defines success when it comes to the U.S. retaliatory campaign.

On Friday night, the U.S. military launched an air assault on dozens of sites in Iraq and Syria used by Iran-backed militias and the Iranian Revolutionary Guard. The military then launched strikes overnight Sunday across several Yemeni provinces allegedly held by the Houthi rebels, an attack the U.S. said targeted underground missile arsenals.

Sullivan told Bash that the U.S. will “take further action” when it comes to more strikes in the region, but declined to describe what such action looks like “because I don’t want to telegraph our punches.” He also refused to rule out whether the military would launch strikes inside Iran, a move that could very likely bring the U.S. into yet another war in the Middle East.

“We are not looking to take the United States to war. So we are going to continue to pursue a policy that goes down both of those lines simultaneously, that responds with force and clarity, as we did on Friday night, but also that continues to hew to an approach that does not get the United States pulled into a war that we have seen too frequently in the Middle East,” Sullivan said.

“Past presidents have had to deal with a significant number of American casualties and American deaths in the Middle East because of war,” he continued. “This president is looking to defend our interests and to defend our troops.”

During a separate appearance on NBC’s “Meet the Press” Sunday, Sullivan told moderator Kristen Welker that the U.S. government is still assessing the damage from the strikes and could not confirm whether the attacks resulted in any civilian casualties or deaths of militant leaders.

“We do not have, at this time, any confirmation of any civilian casualties. Our military is still looking at that,” the adviser said. “What we do know is that the targets we hit were absolutely valid targets from the point of view of containing the weaponry and the personnel that were attacking American forces. So, we are confident in the targets that we struck, and I will defer to a final analysis the question of who was taken out among militant leaders.”

Militia groups in the Middle East said they have intensified their attacks on ships in the Red Sea and on U.S. bases due to Israel’s ongoing bombardment of Gaza, which escalated after Hamas launched a deadly attack on Oct. 7 against the country and took hostages.

Despite Israel now being accused at the international level of Palestinian ethnic cleansing, apartheid and genocide, the U.S. continues to be Israel’s strongest ally, supporting the country diplomatically and financially.

Sullivan told Welker that the U.S. does not believe the attacks by Houthi rebels on ships in the Red Sea are “entirely tied to the war in Gaza,” though the rebels themselves have said their attacks are justified due to Israel’s actions.

“Those attacks will not discourage Yemeni forces and the nation from maintaining their support for Palestinians in the face of the Zionist occupation and crimes,” Houthi military spokesman Brig. Gen. Yahya Saree told The Associated Press. “The aggressors’ airstrikes will not go unanswered.”