By Mohammed Salem

GAZA, Dec 11 (Reuters) Unidentified gunmen killed three sons of a Palestinian intelligence chief loyal to President Mahmoud Abbas in Gaza today after shooting at a car dropping the children at school, police and hospital officials said.

The attack, in which an adult bystander was also killed, came a day after gunmen shot at the interior minister's convoy in Gaza amid growing tension between the governing Hamas Islamist movement and Abbas's Fatah faction.

Interior Minister Saeed Seyam, a senior Hamas leader, was unharmed in that incident.

Police said two other children were wounded in today's attack. The intelligence chief, Baha Balousha, was not in the car when it was attacked.

Initial accounts from residents suggested the children had been killed in crossfire when gunmen opened fire on Hamas policemen near the school.

Residents said the gunmen fled with the Hamas policemen in pursuit. Hospital officials said the dead boys were aged between 6 and 9.

Tensions between Hamas and the formerly dominant Fatah faction in the Gaza Strip and the Israeli-occupied West Bank have spiralled since Hamas took power in March, sometimes spilling over into street battles.

Islamist Hamas has refused international demands that it recognise Israel and renounce violence, prompting a Western aid embargo that has deepened Palestinian poverty.

Reuters SP DS1220