Donald Trump stunned the world by launching an air strike in Syria last week. Picture: AP Photo/Alex Brandon

Speaking on Sunday in his first televised interview, HR McMaster indicated that the US was not seeking to act unilaterally to oust Syrian President Bashar al-Assad.

General McMaster pointed to dual US goals of defeating the Islamic State group and removing Mr Assad.

But he suggested that Mr Trump was seeking a global political response for regime change from US allies as well as Russia, which he said needed to re-evaluate its support of Syria.

“It’s very difficult to understand how a political solution could result from the continuation of the Assad regime,” General McMaster told Fox News Sunday.

“Now, we are not saying that we are the ones who are going to effect that change. What we are saying is, other countries have to ask themselves some hard questions. Russia should ask themselves, ‘Why are we supporting this murderous regime that is committing mass murder of its own population?’”

President Donald Trump speaks at Mar-a-Lago resort in Florida. Picture: AP Photo/Alex BrandonSource:AP

After last Tuesday’s chemical attack in Syria, Mr Trump said his attitude toward Assad “has changed very much” and Secretary of State Rex Tillerson said “steps are under way” to organise a coalition to remove him from power.

But as politicians called on Mr Trump to consult with Congress on any future military strikes and a longer-term strategy on Syria, Trump administration officials sent mixed signals on the scope of US involvement.

While US ambassador to the United Nations Nikki Haley described regime change in Syria as a US priority and inevitable, Mr Tillerson suggested that last week’s American air strikes in retaliation for the chemical attack hadn’t really changed US priorities toward ousting Mr Assad.

Pressed to clarify, General McMaster said the goals of fighting IS and ousting Syria’s President were somewhat “simultaneous” and that the objective of the missile strike was to send a “strong political message to Assad”.

He did not rule out additional strikes if Mr Assad continued to engage in atrocities against rebel forces with either chemical or conventional weapons.

“We are prepared to do more,” he said.

“The President will make whatever decision he thinks is in the best interest of the American people.”

Donald Trump’s top military adviser HR McMaster. Picture: Picture: AP Photo/Susan WalshSource:AP

Reluctant to put significant troops on the ground in Syria, the US for years has struggled to prevent Mr Assad from strengthening his hold on power.

US-backed rebel groups have long pleaded for more US intervention and complained that Washington has only fought the Islamic State group.

So Mr Trump’s decision to launch the strikes, which President Barack Obama declined to do after a 2013 chemical attack, has raised optimism among rebels that Mr Trump will more directly confront Mr Assad.

Several US politicians said on Sunday that the decision shouldn’t entirely be up to Mr Trump.

Senator John Cornyn of Texas, the number two Republican in the Senate, praised Mr Trump’s initial missile strike for sending a message to Mr Assad, Russia, Iran and North Korea that “there’s a new administration in charge”.

But he said Mr Trump now needed to work with Congress to set a future course.

“Congress needs to work with the President to try and deal with this long-term strategy, lack of strategy, really, in Syria,” he said.

“We haven’t had one for six years during the Obama administration, and 400,000 civilians have died and millions of people have been displaced internally and externally in Europe and elsewhere.”

The guided-missile destroyer USS Porter launches a tomahawk land attack missile in the Mediterranean Sea as the United States blasted a Syrian air base with a barrage of cruise missiles in fiery retaliation for a gruesome chemical weapons attack against civilians. Picture: Mass Communication Specialist 3rd Class Ford Williams/US Navy via APSource:AP

Maryland Democratic senator Ben Cardin agreed.

“What we saw was a reaction to the use of chemical weapons, something I think many of us supported,” he said.

“But what we did not see is a coherent policy on how we’re going to deal with the civil war and also deal with ISIS.”

Still, Republican senator Lindsey Graham said he believed that Mr Trump didn’t need to consult with Congress.

“I think the President has authorisation to use force,” he said.

“Assad signed the chemical weapons treaty ban. There’s an agreement with him not to use chemical weapons.”

Their comments came as Mr Tillerson was making the Trump administration’s first official trip this week to Russia, a staunch Assad ally.

In interviews on broadcast Sunday, Mr Tillerson said defeating the Islamic State group remains the top focus.

Once that threat “has been reduced or eliminated, I think we can turn our attention directly to stabilising the situation in Syria”, he said.

“We’re hopeful that we can prevent a continuation of the civil war and that we can bring the parties to the table to begin the process of political discussions” between the Assad government and various rebel groups.

The hope, he said, was that “we can navigate a political outcome in which the Syrian people, in fact, will determine Bashar al-Assad’s fate and his legitimacy”.

Ms Haley said “getting Assad out is not the only priority” and that countering Iran’s influence in Syria was another.
Still, Ms Haley said the US didn’t see a peaceful future Syria with Mr Assad in power.