The National Investigation Agency (NIA) has sought detailed information from the Maharashtra ATS about the seizure of over seven kg of natural uranium worth about Rs 21.30 crore, an official said on Friday.

The Nagpada unit of the Anti-Terrorism Squad (ATS) had arrested two persons on Wednesday night and seized 7.100 kg uranium from them, he said.

"During the investigation, it came to light that the purity of the highly-radioactive substance is more than 90 per cent," the official said.

The ATS is trying to find out the source of the uranium and the accused are being questioned, he said.

"As it is a sensitive matter, the NIA sought a detailed report from the ATS about the uranium seizure," he added.

Accordingly, the ATS on Friday gave a copy of the FIR to the NIA officials and also provided other necessary information related to the case, the official said.

However, it is not yet clear whether the NIA is also starting an investigation into the case, he said.

Another official had earlier said that the seized uranium was sent to the Bhabha Atomic Research Centre (BARC) at Trombay for analysis and the report received from the research centre mentioned that the substance was natural uranium, which is "highly radioactive and dangerous to human life".