Palestinian security forces shot and wounded three masked Palestinian gunmen at a Gaza checkpoint this evening.
A senior Palestinian security official said the men were in a convoy of three cars which launched a rifle-propelled grenade and opened fire at the checkpoint when challenged to stop.
He said three of the armed men were wounded and transferred to a Gaza hospital. The others were detained.
A joint statement issued by the militant wing of the Islamist movement Hamas and the Palestinian Popular Resistance Committees said the security forces opened fire on them as they returned from a mission to fire a mortar shell into Israel.
The Israeli army said it was not aware of any mortar attack into Israel from Gaza.
Israel Radio reported Palestinian police put up checkpoints to capture an Israeli undercover unit believed to be operating in the area. The army was not immediately available to comment on the radio report.