All India Majlis-e-Ittehad-ul-Muslimeen President Asaduddin Owaisi on Saturday filed a petition in the Supreme Court challenging the amendments to the Citizenship Act.

“AIMIM will fight this battle to preserve a plural, secular constitutional democracy in Bharat,” Owaisi tweeted. “This fight will be before every possible forum and using every constitutional tool available to us.”

The contentious amendments allows citizenship to persecuted people of six communities – but not Muslims – from Bangladesh, Pakistan and Afghanistan, provided they have resided in India for six years. The cut-off date is December 31, 2014. The amendments were approved by both Houses of Parliament this week and were signed into law by President Ram Nath Kovind on Thursday night.

There is a widespread fear in the North East that populations defined as indigenous to the region will be culturally and physically overrun by migrants as a result of this law’s provisions. Elsewhere in India, the bill has been opposed due to its allegedly discriminatory view towards Muslims.

The Hyderabad lawmaker has been one of the most vocal opponents of the Centre’s move. On Monday, Owaisi had said that the Citizenship Amendment Bill was “even worse than [German dictator] Adolf Hitler’s laws”. Following a fiery speech in the Lok Sabha during a debate on the bill, Owaisi tore up a copy of the bill, calling it unconstitutional. Owaisi claimed that the bill was against the basic principles of the Constitution and aimed at making Muslims stateless, which could cause another partition of the country.

Trinamool Congress MP Mahua Moitra and Congress MP Jairam Ramesh on Friday moved the Supreme Court challenging the constitutional validity of the amendments. The Indian Union Muslim League had moved the Supreme Court against the amendments on Thursday, while the Congress had said it will take the matter to the top court as well.