CHRONOLOGY - Israeli-Hamas violence since truce ended

(Reuters) - Israel killed a senior Hamas leader in an air attack on his home on Thursday, striking its first deadly blow against the top ranks of the Islamist group in a Gaza offensive that has claimed more than 400 Palestinian lives.

Here is a timeline of events since Hamas ended a truce earlier in December:

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

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

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

December 27 - Israel launches air strikes on Gaza in response to almost daily rocket and mortar fire that intensified after Hamas ended the cease-fire.

December 28 - Hamas says an Israeli air strike destroys a laboratory building at the Islamic University, a significant cultural symbol of Hamas.

-- Israeli aircraft bomb some 40 smuggling tunnels in the Gaza Strip that provide a lifeline to the outside world.

December 29 - Israel steps up its air strikes and bombs the Hamas-run Interior Ministry, the first air strike targeting a government building in the offensive.