Four people suspected to have links with Islamic State have been arrested in Hyderabad as part of the nation-wide crackdown, police sources said.

The National Investigation Agency (NIA) with the help of local police picked up the youth from different places in the city since Thursday night.

The crackdown in various states comes in the wake of intelligence alerts about the possible terror attacks in the country ahead of the Republic Day.

The arrested youth were reported to be under surveillance by the security agencies for their alleged activities on the social media. According to sources, the NIA is on the lookout for five more suspects.

Hyderabad witnessed arrests of a few IS sympathisers and an alleged recruiting agent, a woman, last year. Three youths from the city were arrested at Nagpur airport last month when they were about to board a flight to Srinagar. Police said they were planning to go to Iraq and Syria via Pakistan and Afghanistan to join IS.

Last year, police also counselled more than a dozen youth along with their parents as they were found to be surfing IS material over the internet.