CAIRO (Reuters) - Islamic State called on insurgents in Egypt's Sinai Peninsula on Monday to press ahead with attacks against Egyptian security forces and continue beheadings, an announcement likely to deepen concerns over ties between the militant groups.

"Rig the roads with explosives for them. Attack their bases. Raid their homes. Cut off their heads. Do not let them feel secure," IS spokesman Abu Muhammad al-Adnani said in a statement released online.

(Reporting By Stephen Kalin; Editing by Michael Georgy and Andrew Heavens)