A Hamas security man surveyed the scene on Monday -- 10 activists drawn by a Facebook page invitation to a Gaza rally for Palestinian unity.

"Where's the revolution?" he asked with a note of sarcasm.

Within minutes, security forces of the enclave's ruling Islamist movement moved into Gaza's main square. Witnesses said one of the security men punched the organiser of the rally and the other nine protesters obeyed orders to disperse.

"We are a group of independent youth. The Egyptian and the Tunisian revolutuions moved us and gave us a feeling youth can make a change," the organiser, Ahmed Arar, told reporters before the gathering was broken up.

He said the demonstrators wanted to dissolve the two rival administrations in the Gaza Strip and the West Bank, where Hamas's rival, President Mahmoud Abbas of Fatah holds sway, and promote the formation of a unity government.

Activists had called for the rally on a page of the social networking site Facebook. Ehab al-Ghsain, spokesman of Hamas's Interior Ministry in Gaza, said the rally's organisers had failed to obtain required permits.

"They were spoken to and asked to follow legal procedures," Ghsain said. "We stress our support for freedom of expression."

Hamas seized Gaza from forces loyal to Abbas in a brief civil war in 2007. Egyptian-led unity efforts have failed to reconcile the two sides.

(Writing by Nidal al-Mughrabi and Jeffrey Heller; editing by Samia Nakhoul)