GAZA, June 14 (Xinhua) -- United Nations Envoy to the Middle East Nicolai Mladinov met on Friday in Gaza with Islamic Hamas movement's leaders to help defuse growing tension with Israel, sources close to Hamas said.

The sources, which spoke on condition of anonymity, told Xinhua that Mladinov arrived in Gaza earlier on Friday from Israel and met with the leadership of the movement in the Gaza Strip, which Hamas has been ruling since 2007.

Overnight and early on Thursday, Israeli war planes attacked several facilities and posts in eastern and southern Gaza Strip in response to two rockets attacks carried out by anonymous militants. No one claimed responsibility for the attacks.

Mladinov visited Gaza on Friday, when the Palestinians join the weekly anti-Israel rallies, better known as the Great March of Return and Breaking the Israeli Siege, which has been going on since the end of March last year.

The Highest Commission of the Great March of Return called on the Gaza Strip's populations to join the weekly protests to reject the Israeli plans to annex large parts of the West Bank.

Since the rallies started last year, medics said that the Israeli army killed more than 300 demonstrators and wounded more than 17,000 others by live ammunition.