NORTH SINAI, Aug 3 (Aswat Masriya) - A boy was killed and four people were seriously injured after a mortar shell fell on a house in North Sinai on Sunday. 

The shell fell in Sheikh Zuwied's Shalak village after confrontations between the army and "extremists", a security source told Aswat Masriya. 

The source added that another shell has fallen in a residential area in Arish, but no causalities were reported. 

Egypt's security forces have launched intensive crackdowns in Sinai to arrest militants that have been increasingly targeting police and military personnel and installations since the ouster of former President Mohamed Mursi last year.