India's Supreme Court today refused to put on hold the implementation of the Citizenship (Amendment) Act (CAA), which has sparked nationwide protests, and gave the central government four weeks to respond to petitions challenging the constitutional validity of the law passed by parliament.

A bench headed by Chief Justice of India Justice SA Bobde said a five-judge constitution bench will be set up for dealing with the petitions on the citizenship law.

The court made it clear that it would not put the law on hold without hearing the Indian government.

A bench headed by Chief Justice SA Bobde is hearing 143 petitions, mostly challenging the validity of the CAA.

"This matter is uppermost in everyone's mind," said Chief Justice Bobde.

The bench said it will pass order granting any interim relief to petitioners opposing the CAA after four weeks.

The apex court also restrained all High Courts across India from hearing pleas on the CAA till it decides the petitions.

The CAA offers citizenship to religious minorities from Bangladesh, Pakistan and Afghanistan who faced "persecution" there and came to India till 2014.

The opponents of the law term it "divisive" because it keeps Muslims from its purview and gives citizenship to Hindus, Buddhists, Christians, Jains, Sikhs and Parsis from the three neighbouring countries of India.