Jihadist websites also posted pictures showing armed men sitting in front of microphones in a broadcasting studio and brandishing Kalashnikov assault rifles.
"They took Radio Sirte yesterday. Since then they have been broadcasting (verses from) the Koran and speeches by (IS chief Abu Bakr) al-Baghdadi," a resident of the central city told AFP by telephone.
The resident said speeches of IS spokesman Abu Mohammed al-Adnani were also being played on the air.
"They could take advantage of the absence of any central government authority to transform the city into an Islamic emirate as they did in Derna," an eastern city held by jihadist groups including IS.
The man, who declined to be named, said the gunmen apparently seized the radio "as a first step to communicate with the population".
"The situation in Sirte is very complex," he said, because many radical groups have a foothold there.
Sirte is a bastion of Ansar al-Sharia, an Islamist blacklisted by the United Nations and the United States.
And militias of the Islamist-backed Fajr Libya (Libya Dawn) coalition control some parts of Sirte, and launched attacks against key oil installations nearby in December.
Earlier today, gunmen raided the Al-Bahi oil installation south of Sirte, causing heavy damage but no casualties before being repelled, guards at the privately run site said.
The security spokesman for Libya's oil facilities, Ali al-Hassi, pointed a finger of blame at IS, whose militants attacked the nearby Al-Mabrouk field on February 3.
Taking advantage of the chaos, IS has claimed a string of deadly attacks. The latest targeted a luxury hotel in Tripoli on January 27, when nine people were killed, five of them foreigners.
You’ve reached your limit of {{free_limit}} free articles this month.
Subscribe now for unlimited access.
Already subscribed? Log in
Subscribe to read the full story →
Smart Quarterly
₹900
3 Months
₹300/Month
Smart Essential
₹2,700
1 Year
₹225/Month
Super Saver
₹3,900
2 Years
₹162/Month
Renews automatically, cancel anytime
Here’s what’s included in our digital subscription plans
Exclusive premium stories online
Over 30 premium stories daily, handpicked by our editors


Complimentary Access to The New York Times
News, Games, Cooking, Audio, Wirecutter & The Athletic
Business Standard Epaper
Digital replica of our daily newspaper — with options to read, save, and share


Curated Newsletters
Insights on markets, finance, politics, tech, and more delivered to your inbox
Market Analysis & Investment Insights
In-depth market analysis & insights with access to The Smart Investor


Archives
Repository of articles and publications dating back to 1997
Ad-free Reading
Uninterrupted reading experience with no advertisements


Seamless Access Across All Devices
Access Business Standard across devices — mobile, tablet, or PC, via web or app
