In another sign of spiralling unrest ahead of a Palestinian election, masked gunmen have stormed into a club for United Nations workers in Gaza City – attacking the security guard and blowing up the drinking hall.It is the first such attack on a UN target in the Strip where the organisation is generally viewed with sympathy. But this is a time of growing unease, highlighted by the announcement by several militant groups, including Hamas, that a de facto truce with Israel is over. The move is a slap in the face for Palestinian President Mahmoud Abbas who has vowed to restore order to Gaza. Chaos there has been increasing since the departure of Israeli troops in September after a 38-year presence. Israel says the mayhem – that includes a spate of kidnappings – could have repercussions for any hopes of peacemaking. An Italian activist seized on Sunday was later freed. Against this backdrop, Israeli leader Ariel Sharon also has other things on his mind – notably minor heart surgery he is due to undergo on Thursday.