Sen. Doug Jones joined five of his colleagues in a bipartisan effort to implore President Trump to rethink his move to withdraw from northern Syria and abandon America’s Kurdish allies while giving Turkey the capability of military strikes in the area, his office announced Thursday.

Jones was one of two Democrats along with Sen. Joe Manchin of West Virginia to write a letter to Trump expressing “grave concerns about our national security and foreign policy.” Independent Sen. Angus King of Maine and Republican Sens. Joni Ernst of Iowa, Martha McSally of Arizona and Dan Sullivan of Alaska also signed on to the letter.

“We come to you in the sincerest bipartisan fashion because of our grave concerns about our national security and foreign policy,” the six senators wrote. “We hope that you will urge Turkey to end their offensive and find a way to a peaceful resolution while supporting our Kurdish partners to ensure regional stability.”

Trump’s rationale for the withdrawal was to fulfill his campaign promise of getting the country out of endless wars. But the senators said the Syrian move harms national security.

“We are aware that one of your goals is to reduce US involvement in long term wars in the Middle East, and many of us are supportive of those efforts,” the senators wrote. “However, leaving so abruptly without protection for those partners who have been with us in the fight against ISIS is not only perilous for them, but also dangerous for us and our national security.”

While not a party to the letter, Richard Shelby, Alabama’s Republican senior senator, said “a strategic and bipartisan effort” is needed in foreign policy.

“Our policy on Syria has remained one of the leading foreign policy challenges for the United States,” the senator said in a statement to AL.com. “Although there is no easy resolution, I believe our path forward warrants a strategic and bipartisan effort to reach a solution that prioritizes American leadership. I believe the recent cease-fire [in northern Syria] is a good first step in achieving this goal.”

The senators’ appeal comes a day after the House passed a bipartisan resolution condemning the withdrawal from northern Syria by a vote of 354-60. Reps. Mo Brooks, R-Huntsville, and Bradley Byrne, R-Mobile, who is running for the Republican nomination to challenge Jones in November, were the lone members of Alabama’s congressional delegation to vote against the resolution.

On Thursday, Sen. Rand Paul, R-Ky., blocked a similar resolution from being taken up in the Senate.

“The resolution that’s being offered is simply a way to have petty partisan criticism of the president infect this body,” Paul said, according to Politico.

AL.com reporter John Sharp contributed reporting