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 ceasefire focused 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 ceasefire, which expires the next day with a surge of cross-border fighting.

December 24 - Gaza Palestinian militants ratchet up rocket fire toward 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".

December 31 - Emergency session of U.N. Security Council to consider resolution drafted by Arab countries calling for immediate ceasefire adjourns without a vote.

January 1 - Israel kills Nizar Rayyan, a hardline Hamas leader, in an air attack on his Gaza Strip home.

January 2 - Palestinian official says that Egypt began exploratory talks with Hamas to halt the bloodshed.

January 3 - Israel launches ground offensive in the Gaza Strip, sending tanks and infantry into battle with Hamas fighters. Israel says calls up tens of thousands of reservists.

January 4 - Israelis cut the strip in half from the border fence to the Mediterranean. Troops and armor ring Gaza City. Israel rejects possibility of a ceasefire at this stage.

January 5 - French President Nicolas Sarkozy, on a peace mission to the Middle East, and U.S. President George W. Bush, in his final weeks in office, both appeal for a ceasefire.

January 6 - Ground offensive widens. Total deaths recorded by Palestinian medics reach 588. Nine Israelis, including three civilians hit in rocket attacks, have been killed.