The Chief Constable of the PSNI Matt Baggott is tonight warning of further attacks by dissident Republicans.
Mr Baggott has urged the public to be vigilant after a grenade was thrown at PSNI officers in west Belfast last night.
Óglaigh na hÉireann has said it carried out the attack which has left one officer with severe arm injuries.
Mr Baggott said the threat from dissidents is "higher than ever".