Witnesses said that the exchanges of fire lasted for several hours.
 
They said that groups of armed men were continuing to patrol Gaza City early on Wednesday, and roadblocks - which should have all been removed under the terms of the ceasefire - were still in place.
 
The truce between forces loyal to Haniya and those supporting Abbas came into force at 11pm (21:00 GMT) on Tuesday, but the factional fighting has continued regardless.