Israeli planes have carried out 13 air strikes on the Hamas-ruled Gaza Strip, Palestinian sources have told the BBC.

巴勒斯坦方面消息，以色列空军近日对哈马斯统治的加沙地带发动了13次空袭。

Four of the strikes took place near the town of Khan Younis, where two Israeli soldiers were killed in clashes with Palestinian fighters last week.

The Israeli military has told the BBC the operation was targeting four weapons factories.

The strikes are the most serious for more than a year, says the BBC's Jon Donnison from Jerusalem.

The director of ambulance and emergency in the Palestinian Ministry¹ of Health, Dr Muawiya Hassanein, said that three children including an infant were slightly injured by flying debris（碎片，残骸） .

Witnesses and Hamas officials said the Israeli raids targeted metal workshops, farms, a milk factory and small sites belonging to the military wing of Hamas.

'Retaliation²'

"Israel will not tolerate terroristic activity inside Gaza that threatens Israeli citizens," the Israeli military said in a statement released to the BBC.

Palestinian news agencies reported that Israeli aircraft dropped leaflets（传单） over parts of Gaza on Thursday warning residents of retaliation（报复，反击） for last Friday's killings³ of the soldiers in Khan Younis.

They were the first Israeli soldiers to be killed in hostile fire in Gaza in over a year. The military wing of Hamas claim responsibility for those attacks.

Hamas said police stations and training facilities were among the targets of Israel's overnight raids.

Tensions in the region are running high after a recent Israeli government announcement of plans to build 1,600 new homes for Jewish people in East Jerusalem, which the Palestinians want as a capital of a future state.

Militants⁴ in the Gaza Strip have recently stepped up rocket fire directed at Israel.

On Wednesday, they fired a rocket into an empty field in southern Israel, but there were no reports of casualties（人员伤亡） or damage, military sources said.