The task force’s formation “gives us hope that our government and our Congress are doing all they can to bring our loved one and all Americans held abroad home,” said Samar Hamwi and Mouna Kamalmaz, the sister and mother, respectively, of Majd Kamalmaz, a Virginia therapist who has been missing since being stopped at a Syrian checkpoint in 2017.

Mr. Deutch co-sponsored legislation passed last year intended to strengthen U.S. efforts to return Americans held abroad.

The Robert Levinson Hostage Recovery and Hostage-Taking Accountability Act, which passed Congress and was signed into law in December, establishes criteria for wrongful detention and codifies the U.S. government response. The measure is named for a retired FBI agent—Mr. Deutch’s constituent—who has been missing in Iran since 2007; his family said last year they believed he had died in custody.

Former President Donald Trump’s administration placed particular emphasis on securing the release of U.S. citizens held hostage or wrongfully detained abroad, including evangelical pastor Andrew Brunson, who had been held in Turkey; Xiyue Wang, a Princeton graduate student held in Iran; and a pair of Americans held by Iran-backed Houthi rebels in Yemen. Prior to the passage of the Levinson measure, the government response was limited to a presidential policy directive first issued in 2015 that could be revoked at any time.

The December legislation made permanent three executive branch entities: the Special Envoy for Hostage Affairs at the State Department, the interagency Hostage Recovery Fusion Cell, and the Hostage Response Group at the National Security Council.

The congressmen’s efforts have the support of a pair of organizations that work on behalf of detained Americans and their families.

Mouaz Moustafa, executive director of the Syrian Emergency Task Force, said the task force will serve as “an important resource for Americans seeking freedom for their loved ones held by the Assad regime.”

The James W. Foley Legacy Foundation, named for the American journalist who was kidnapped and killed in Syria, tracks the cases of Americans held abroad as well as government efforts to secure their release.

By the foundation’s count, 53 Americans are currently being held hostage or wrongfully detained in 13 countries, from Afghanistan to Cuba.

Margaux Ewen, executive director of the Foley foundation, noted that until Myanmar’s release of U.S. journalist Nathan Maung this week, no Americans had been released in the seven months since President Biden’s election.

“We need the president to make this a priority,” she said, adding the task force can help to create a “pressure point” for the administration.