TIMELINE-Israeli-Hamas violence since truce ended

(Reuters) - Israel's offensive in the Gaza Strip killed more than 30 Palestinian civilians on Tuesday, medical officials said, and international efforts to secure a cease-fire focussed on an Israeli demand to prevent Hamas from rearming.

Here is a timeline of events since early December:

December 14 - Hamas leader Khaled Meshaal says the group will not renew a six-month-old truce with Israel.

December 18 - Hamas declares the end of the Egyptian-brokered cease-fire, which expires the next day with a surge of cross-border fighting.

December 24 - Gaza Palestinian militants ratchet up rocket fire towards Israel.

December 27 - Israel launches massive air strikes on Gaza in response to the intensified rocket and mortar fire, killing at least 229 Palestinians.

December 28 - Israeli air strikes hit a building at the Islamic University and target some 40 smuggling tunnels in the Gaza Strip that provide a lifeline to the outside world.

December 29 - Israel bombs the Hamas-run Interior Ministry and declares areas around the Gaza Strip a "closed military zone". Palestinian militants fire rockets deeper into southern Israel.

December 30 - Hamas spokesman Fawzi Barhoum urges Palestinian groups to respond using "all available means" against Israel. Israel says its attacks herald "long weeks of military action".