At least four people are being held hostage at the Congregation Beth Israel in Colleyville, Texas, according to a law enforcement official, CNN reported.
A rabbi is believed to be among the hostages.
FBI negotiators made contact with the person in the building, authorities said.
Police said residents are being evacuated and they advise people avoid the area.
President Biden has been briefed on the developing hostage situation at the synagogue and top members of his national security team are in touch with federal law enforcement leaders, according to a tweet from White House Press Secretary Jen Psaki.