CAIRO (AFP) - Egypt's president on Friday suggested US President Barack Obama's condemnation of a deadly crackdown on Islamists may "encourage violent armed groups".

"The presidency fears statements not based on facts may encourage violent armed groups," it said in a statement responding to Mr Obama's condemnation of Wednesday's carnage when police moved to disperse Islamist protest camps.

"The presidency appreciates US concern for developments in Egypt, but it wished it could have clarified matters," said the statement published by the official MENA news agency.

"Egypt is facing terrorist acts aimed at government institutions and vital installations," the statement said.

Mr Obama on Thursday said he was cancelling a joint military exercise with Egypt, adding he "strongly condemns" the security forces' operation that killed more than 300 people in the Cairo protest camps.