A spokesman for Abbas said: "The president of the Palestinian Authority, Mahmoud Abbas ... considers the executive force, both officers and individuals, illegal and outlawed."
"The executive force is illegal... and will be treated as such if it is not immediately integrated"
Mahmoud Abbas, Palestinian president
The president's spokesman also said the Hamas force would remain illegal until it complied with a previous decision by Abbas to integrate into the established national security apparatus.
A statement from the presidency said: "The executive force is illegal... and will be treated as such if it is not immediately integrated... into legal security services as stipulated by basic law."
Abbas took the decision "in light of the increasing security chaos, numerous assassinations... that do not spare children, and following the failure by the Palestinian groups and security services to respect the law and protect citizens."
Hamas has warned Abbas that it will retaliate if any moves are made against its armed wing.
Khaled Abu Hillal, spokesman for the Hamas-controlled interior ministry, said: "[Abbas' demand] is hasty and we warn against making any move, which will be met with force."
|Haniya has called for an|
end to the tension [AFP]
Just hours after Abbas declared the Gaza-based unit illegal, Hamas said it would double the size of the unit to 12,000 personnel.
Islam Shahwan, a spokesman for the executive force, said: "A decision was taken to increase the number of the executive force to 12,000."
"We call upon all sincere citizens to prepare themselves to join the force," he said.
After agreeing a halt to the violence with Abbas on Friday, Haniya called for "an end to the tension."
"I repeat that we have to prevent any fighting," he said.
However, one spokesman for Hamas-controlled interior ministry has accused Abbas of giving the "green light" for attacks on Hamas security men.
has seen factional violence for several days, with 13 people killed in clashes on Wednesday and Thursday between forces loyal to Abbas' Fatah party and those of Hamas.
Shortly after Abbas's statement, fighting broke out between members of two powerful clans in Gaza City killing three men from one family and injuring nine other people.
It was the first deadly clash since early on Friday.