TIMELINE: Israeli-Hamas violence

(Reuters) - Voicing shock at stark scenes of destruction, U.N. Secretary-General Ban Ki-moon visited the Gaza Strip on Tuesday, and Israel was poised to withdraw its troops.

Here is a timeline of events since a six-month ceasefire between Israel and Hamas in the Gaza Strip ended last month.

December 19, 2008 - Ceasefire expires.

December 24 - Gaza Palestinian militants fire rockets at Israel.

December 27 - Israel launches air strikes on Gaza, killing at least 229 Palestinians.

December 28 - Israeli air strikes hit the Islamic University and target smuggling tunnels in the Gaza Strip.

December 31 - Emergency U.N. Security Council session on Arab resolution calling for ceasefire adjourns without a vote.

January 1, 2009 - Israel kills Nizar Rayyan, a hardline Hamas leader, in an air attack on his Gaza Strip home.

January 3 - Israel launches a ground offensive in the Gaza Strip, sending tanks and infantry into battle with Hamas.

January 4 - Israelis cut the strip in half from the border fence to the Mediterranean. Troops and armor ring Gaza City.

January 5 - French President Nicolas Sarkozy, on a peace mission, and U.S. President George W. Bush, call for ceasefire.

January 6 - Israeli shelling kills 42 Palestinians at a U.N. school in Jabalya refugee camp where civilians had sheltered.

-- Egypt, backed by France and other European powers, proposes an immediate ceasefire.

January 8 - Rockets fired from Lebanon strike northern Israel, wounding two people.

-- The U.N. Security Council votes for a resolution calling for an immediate ceasefire in Gaza, but the United States abstains, citing Egyptian-mediated talks on a truce.

-- The U.N. Relief and Works Agency (UNRWA), which distributes the majority of aid in Gaza, suspends its operations after an Israeli tank shell kills an UNRWA driver in a convoy.

January 9 - Israeli Prime Minister Ehud Olmert rejects the U.N. resolution as "unworkable" and, noting Palestinians fired rockets at Israel, says the army will go on defending Israelis.

January 10 - Hamas leader Khaled Meshaal accuses Israel of perpetrating a "holocaust" in Gaza and says his group will not consider a ceasefire until Israel ends its assault.

-- Palestinian President Mahmoud Abbas meets Mubarak in Cairo. Egypt says it will not accept foreign troops on its side of the border with Gaza to stop arms smuggling.

January 11 - Israeli forces edge into the Gaza Strip's most populous area, throwing army reservists into battle.

-- Israel says stopping arms smuggling from Egypt to the Gaza Strip should be done by Egyptian forces and rejects the idea of an international force.

January 12 - Olmert, Israeli Defense Minister Ehud Barak and Foreign Minister Tzipi Livni decide against ordering troops in to engage in all-out urban warfare.

January 13 - Hamas says it has "substantial observations" about an Egyptian ceasefire proposal.

January 14 - Rockets fired from Lebanon strike Israel for the second time in a week.

-- U.N. Secretary General Ban Ki-moon arrives in Cairo and calls again for an immediate ceasefire between Israel and Hamas.

-- A Hamas delegation is holding talks with Egyptian intelligence officials on an Egyptian initiative, but Hamas has said changes to the Egyptian proposals are needed.

-- Human Rights Watch says Israel's daily three-hour break in attacks to facilitate the supply of humanitarian aid to Gazans is "woefully insufficient."

January 15 - Israeli forces push deeper into Gaza city unleashing their heaviest shelling in three weeks of war.

-- An Israeli envoy is to meet Egyptian mediators in Cairo after a Hamas delegation ends talks on Egyptian truce proposal.

-- UNRWA says its compound is struck twice by Israeli fire and three staff members are injured.

-- Ban tells Israel the death toll from fighting has reached an "unbearable point."

January 17 - Israel declares unilateral ceasefire with effect from 0000 GMT. Hamas guerrillas say the war will go on.

January 18 - Hamas announces a ceasefire in the Gaza Strip.

-- There is shooting from both sides after the declarations, but the ceasefire appears to gain strength and Israeli troops begin pulling out of Gaza.

January 19 - Israeli forces press on with a gradual withdrawal.

-- A spokesman for Hamas's armed wing vows to replenish its arsenal of rockets and other weapons.

-- A source in the Hamas administration in the Gaza Strip said 5,000 homes, 16 government buildings and 20 mosques were destroyed and 20,000 houses damaged in the three-week war.

January 20 - Ban Ki-moon visits the Gaza Strip and calls the Israeli attack on a UNRWA compound outrageous and demands an investigation.

-- Two children playing with unexploded ordnance are killed when it detonates, Hamas officials say.