Officials in Gaza said Israeli troops shot and wounded five Palestinians along the border Wednesday and arrested nine fisherman at sea, a week after the two sides agreed a truce.
Medical officials said that army fire injured four Palestinians east of El-Bureij refugee camp in the centre of the strip and a fifth in the north, near the Erez crossing to Israel.
The Israeli military did not confirm any casualties but said troops had responded to several attempts by Gazans to breach the border fence.
"Several Palestinian rioters approached the security fence in several locations...while acting violently, trying to illegally infiltrate Israel through the fence," a spokesman told AFP.
"The soldiers at the scene acted in order to distance the violent rioters and in accordance with the rules of engagement," he said without elaborating.
Elsewhere, "in a new violation of the ceasefire, the Zionist enemy arrested nine citizens and sunk several boats in the sea off the northern Gaza Strip," Hamas interior ministry spokesman Islam Shahwan said in a statement.
The 21 November ceasefire deal brought a halt to eight days of cross-border fighting between Israel and Gaza militants which claimed the lives of 173 Palestinians and six Israelis, two of them soldiers, sources on both sides said.
Palestinians said that as part of the truce, Israel's naval blockade of the coastal territory was eased to allow fishing boats to operate up to six nautical miles from shore, instead of three previously.
A military spokesman told AFP that a patrol boat intercepted a fishing vessel that had sailed beyond the boundary, although he did not specify how far out it was.
"A fishing boat deviated from the designated fishing area in northern Gaza," he said, adding that naval personnel "asked the boat to stop but it didn't, so they apprehended the boat and took the people on board for questioning at Ashdod port" in southern Israel.
There was no confirmation from either side on Wednesday evening if the Gazans had been released.