Violence has erupted in and around the Hamas-ruled Gaza Strip after the end of an Israeli-Palestinian truce.

Israel launched an airstrike on Palestinians firing rockets across the Gaza border. One Palestinian militant was killed. It was the first deadly clash since a six-month-old cease-fire formally ended on Friday.

The Islamic militant group Hamas, which rules Gaza, decided not to renew the truce saying it would return to armed resistance. Israel said it prefers to continue the cease-fire, but if attacked, it will retaliate.

"Unfortunately, rockets launched by terrorists in Gaza continue to rain down on Israeli civilians. And this situation just can't continue," said Israeli spokesman Mark Regev.

Hamas spokesman Fawzi Barhoum blamed Israeli army raids and the closing of border crossings into Gaza for the collapse of the cease-fire.

Barhoum said Israel sought a cease-fire but violated it, and the "Zionist occupation," as he put it, would pay the price.

Meanwhile, a boat carrying a Qatari delegation, Lebanese activists and an Israeli journalist sailed into Gaza from Cyprus carrying symbolic humanitarian aid. It was the fifth boat trip by international activists since the summer in defiance of a crippling Israeli blockade.

One of the passengers, Aed al-Kahtani, who represents a government-funded charity in Qatar, said the people and government of Qatar want to help their needy Palestinian brothers in Gaza.