Israeli warplanes launched several raids on Wednesday in the Gaza Strip after a day of tensions along the border with Israel, said the interior ministry in the Palestinian territory.

Air strikes hit around Gaza's derelict international airport near the southern city of Rafah and in nearby farming areas, without causing casualties, said the ministry, which is run by the Islamist Hamas movement.

Israel's army said it had hit five sites operated by Hamas.

"The (Israel armed forces) will continue to operate in order to protect the civilians of Israel from all Hamas terrorist threats above & beneath ground," spokesman Peter Lerner said on Twitter.

The border between Israel and Gaza -- the scene of a devastating 2014 conflict -- saw a bout of violence on Wednesday, with Israeli tanks firing into the enclave in what Israel said was a response to mortar fire.

There were no reported injuries and no claims of responsibility for the mortar fire.

Hamas and Islamic Jihad, another militant Palestinian group, released separate statements warning Israel against any escalation along the border.

"Hamas holds the Israeli occupation completely responsible for the escalation east of Gaza and the consequences of it," spokesman Sami Abu Zahri said.

"The movement calls on the concerned parties to shoulder their responsibility to stop this aggression and Israeli crimes."

The violence puts pressure on a ceasefire that has held since the last round of hostilities in Gaza ended in summer 2014.

Israel to upgrade ties with NATO
Jerusalem (AFP) May 4, 2016 - Prime Minister Benjamin Netanyahu said on Wednesday that Israel would upgrade its ties with the 28-member NATO military alliance by opening a permanent mission to its Brussels headquarters.

"Israel will accept the invitation and open an office, in the near future," Netanyahu said at the start of a cabinet meeting.

"The countries of the world want to cooperate with us because of our determined fight against terror, our technicological know-how, our intelligence network and other things," his office quoted him as saying.

NATO announced on Tuesday that it agreed that "an official Israeli mission be established at NATO headquarters" with the Israeli envoy to Belgium as head of the mission.

An Israeli expert told AFP that the move was a result of pressure from other NATO members on Turkey, which joined in 1952, to drop its veto on closer alliance ties with its former ally.

"It's a Turkish confidence-building measure vis-a-vis Israel," said Tommy Steiner, an expert on NATO-Israel ties at the Institute for Policy and Strategy near Tel Aviv.

"Since the introduction of the new (NATO) partnership policy in 2014 Israel was formally invited," he said. "But Israel never did that because there was a Turkish veto on such a measure."

Turkey was a key regional ally of Israel until the two cut ties in 2010 over the deadly storming by Israeli commandos of the Mavi Marmara, a Turkish aid ship bound for Gaza, which left 10 Turkish activists dead.

After years of bitter accusations and rhetoric the two sides held secret talks in December on a rapprochement, with another round taking place in February in Geneva

"Following the Mavi Marmara affair, Turkey blocked everything (at NATO) concerning Israel," a Brussels-based diplomat told AFP. "In order to avoid discrimination (NATO) did not therefore open any other foreign mission."

"After five years the Turks lifted their objections" allowing for the establishment of missions for Israel and for other states, the diplomat said.

Steiner said that the geographically and politically diverse NATO grouping would not invite Israel into a full-fledged mutual-defence pact.

"Israel is not going to be a full member, it's not on the cards," he said. "Israel will be officially accredited to NATO, it will have a permanent mission at NATO headquarters as a partner."

Israel already participates in military exercises with NATO members other than Turkey, notably the United States.