The house of representatives has mandated its Committees on Ethics and Privileges and that of Foreign Affairs to investigate the alleged sexual misconduct against three members of the green chamber.
It called on the United States Ambassador to provide Nigeria with proof that the accused committed such crime.
It said none of the accused persons was interrogated by the US.
However, one of the alleged lawmakers, Mark Gbillah (APC, Benue) has denied the allegation, saying that the US Ambassador to Nigeria Mr James Entwhistle was out to tarnish his image and the Nigeria House of Representatives.
He said that no such incident occurred as reported by the ambassador, and insisted that the envoy should provide proof to support his allegation.
Gbillah was accused with Samuel Ikon (PDP, Akwa Ibom) and Mohammed Gololo (APC, Bauchi) of the crime.
Meanwhile, Speaker of the house, Mr Yakubu Dogara, urged Nigerians to tread with caution on the matter until the persons involved were proven guilty.