Sources tell NY1 that the city has reached a settlement with Muslims who challenged police surveillance on them as unconstitutional.

The lawsuit was filed in the wake of revelations that city police spied on Muslim groups as part of an effort to prevent terrorist attacks.

Sources say the agreement was announced in a letter filed Friday.

Some details cannot be disclosed because of a confidentiality agreement.

There is no official word from either the city or the groups who sued, which include the ACLU.

At the time, the NYPD and the city defended the surveillance as a legal and appropriate anti-terrorism tactic.