Israel-based Teva Pharmaceutical Industries said on Tuesday it now expects its $40.5 billion acquisition of the generic drug activities of Allergan (AGN.N) to be completed by June.

Teva (TEVA.N), the world's biggest generic drugmaker, previously expected the deal would close by the end of the first quarter with the potential for it to be slightly delayed into April.

While significant progress has been made, "Teva now anticipates that completing the acquisition could take as long as June 2016, based upon its current estimate of the timing to obtain clearance from the United States Federal Trade Commission," it said in a statement.

Teva said it continues to work closely with the FTC to obtain U.S. regulatory approval. Last week it received regulatory approval from the European Commission for its acquisition, subject to certain divestitures.