CAIRO, Dec 26 (Reuters) - An Islamist group in Egypt's Sinai Peninsula threatened to launch a crusade against drug use and cigarette smoking in the lawless desert region on Wednesday, prompting fears about the growing influence of radical groups in post-revolutionary Egypt.
The country's new constitution, adopted this week, states that the principles of sharia, Islamic law, are the main source of legislation.
Rights groups say the document contains vague language, such as references to "national" morals, which they believe hardliners can take advantage of to impose religious restrictions on people.
The Sinai vigilante group, which calls itself "Group for Promotion of Virtue and Prevention of Vice," issued its warning in a leaflet distributed around North Sinai, saying its punishment of those who did not comply would be "very harsh".
"This statement is the first warning, and there will be no second. It is directed at those trading in drugs, specifically cigarettes," it said. "Those traders are destroying the families of Sinai, and flouting God's laws."
Local security sources said little was known about the group and that it had never issued such statements in the past.
A crackdown on trade in cigarettes or smoking in public places is likely to be perceived as a radical measure in a heavy smoking nation where puffing on a butt in public is socially acceptable and is practically part of the national pasttime.
Efforts to impose central authority in the desert region near the Israeli border have been slow since the fall of veteran autocrat Hosni Mubarak in the 2011 uprising, complicated by locals' ingrained hostility to the government in Cairo.
Islamist president Mohamed Mursi launched a concerted effort to reestablish control of Sinai following an Aug. 5 attack in which 16 border guards were killed. But a Nov. 3 gun attack in which three policemen died underlined the challenge still facing the authorities. (Reporting by Yousri Mohamed; Writing by Shaimaa Fayed; Editing by Maria Golovnina)