The Enforcement Directorate raided premises linked to Shiv Sena MLA Pratap Sarnaik in Maharashtra on Tuesday in connection with a money laundering case being probed against a security service provider company and others, official sources said.
His party called the raids a "political vendetta" and said the Maharashtra government or its leaders will not surrender to pressure from anyone.
Sources said the searches are being conducted by the central agency at 10 locations in Mumbai and neighbouring Thane.
CRPF personnel were seen assisting ED sleuths during the operation that was launched early morning.
"The searches are being conducted on the Tops group (a company in the business of providing security) promoters and related people, including some politicians," an official source said.
Agency officials also questioned the MLA's son Vihang. The probe, sources said, is related to some overseas transactions by the entities involved.
Sarnaik, 56, represents the Ovala-Maijwada constituency in the Maharashtra Legislative Assembly and is also a spokesperson for his party.
The legislator was in news when he wrote a letter seeking re-opening of an alleged abetment to suicide case of 2018 in which Republic TV's editor-in-chief Arnab Goswami was arrested by Mumbai Police recently.
Goswami is now out on bail.
Sarnaik had also demanded a unanimous resolution in the Maharashtra legislative assembly for legal action against actress Kangana Ranaut, who, he said, has "maligned" the image of Maharashtra and Mumbai through her tweets.
"This action (ED raids) is definitely a political vendetta. The ED or other agencies should not work as if a branch of a political party," Shiv Sena MP Sanjay Raut told reporters.
He said Sarnaik's properties were raided while the latter was not at home, and added that no matter how many notices are issued, only truth shall prevail in Maharashtra. Raut also said there is no ban on probes by an agency and it can take action if there is evidence.
"But, you want to mentally harass the people related to the (state) government. These actions will backfire on you. And I think that time is nearing," he said.
The Shiv Sena was earlier an ally of the BJP but snapped ties with it last year over the issue of sharing the chief ministerial post and it is in power in the state along with the Nationalist Congress Party and the Congress.