Last week, some 50 mid-level US officials signed a so-called “dissent channel” cable calling for military action to force Syria’s Bashar al-Assad to agree to peace talks.

Secretary of State John Kerry sat down Tuesday for an exchange of views with the US diplomats who challenged White House policy and called for air strikes on Syria.

Last week, some 50 mid-level US officials signed a so-called “dissent channel” cable calling for military action to force Syria’s Bashar al-Assad to agree to peace talks.

Rather than express annoyance at the rebuke, Kerry dubbed the memo “very good,” fueling speculation in Washington that he too is frustrated with President Barack Obama’s cautious policy.

While widely reported, the contents of the cable remain classified, so State Department spokesman John Kirby has refused to address the issues raised by the dissident diplomats.

But on Tuesday, he confirmed that Kerry had met with 10 of the memo’s authors. Kerry was mostly in “listening mode,” Kirby said, but there was an exchange of views.

“I believe the secretary came away feeling that it was a good discussion and that it was worth having,” Kirby said.

“He appreciated their views and — just as critically — their firm belief in the opportunity that they have to express those views.

“And so, they had a good 30-minute or more conversation.”

The US military is engaged in Syria, but US air strike planners and US-backed militia fighters are concentrating their fire on the violent extremist IS group.

Assad, meanwhile, is hammering the moderate opposition, with support from Russia. Many US diplomats now feel more must be done to bring an end to the five-year-old civil war.

There is no sign that Obama, with only seven months left in his presidency, wants to open up a new and dangerous front in America’s troubled military interventions in the Middle East.

But Kirby — while repeating the administration’s mantra that “there is no military solution to this conflict” — said it would be “imprudent and irresponsible… not to consider other options.”

“And those other options are still, and have been, and are still being considered,” he added.