Those arrested yesterday included three Fatah-affiliated district governors, as well as the two highest Gaza representatives of Palestinian president Mahmoud Abbas, the officials said.
A spokesman for Hamas, Sami Abu Zuhri, declined to confirm the number or the identity of those taken into custody, but he did confirm that the arrests were a response to Fatah's seizures of "Hamas political leaders" in the West Bank.
The two Palestinian organizations have engaged in a bitter and often violent rivalry for several years, culminating in Hamas' violent takeover of Gaza one year ago. Fatah's power in Gaza was largely erased and it was left in control only of the West Bank.
Both groups have periodically carried out arrest sweeps targeting rivals in the territories they control. Several of the men arrested by Hamas on Friday had already been seized in the past and later released.
Hamas initiated the crackdown after a July 25 explosion in Gaza killed five Hamas members and a 6-year-old girl. Hamas blamed Fatah for the deaths and responded by arresting male members of the organization. Fatah denied responsibility, and launched it's own roundup of Hamas men in the West Bank in retaliation.
In all, it is estimated that both sides have seized about 200 of the other groups members, although neither side will reveal an exact number or the identities of those they are holding.