The U.N. chief visited Gaza on Tuesday to give a push to international reconstruction efforts following a devastating summer war, saying the destruction was "beyond description" as Israel allowed the first shipment of construction materials to enter the coastal strip since the fighting ended in August.

Ban Ki-moon's visit, along with the arrival of long-awaited building materials, gave Gazans a rare glimmer of hope in the wake of a 50-day war that flattened entire residential areas and left tens of thousands of people homeless.

"I'm here with a very heavy heart," Ban said to reporters after touring the rubble.

The violence between Israel and the Islamic militant group Hamas ended with a truce but left more than 2,100 Palestinians dead, most of them civilians, according to the United Nations. On the Israeli side, 72 people died, most of them soldiers.

The U.N. chief said the destruction he saw in Gaza was "much more serious" than what he witnessed in the Palestinian territory in 2009 in the aftermath of a previous Israel-Hamas war.

Ban said he told Israeli and Palestinian officials in meetings that "there is no hope for the long-term stability of Gaza without addressing the underlying causes of the conflict."

Two months after the war ended in a stalemate, border restrictions remain largely in place. But Israel has agreed to a U.N.-monitored system to allow the entry of construction materials, and over the weekend, the international community pledged $2.7 billion in reconstruction aid.

Israel, which controls the main cargo crossing into Gaza, called Tuesday's effort a "pilot" initiative, still wary that building materials could be used by Hamas to rebuild its military infrastructure. The U.N. is monitoring the use of construction materials that pass through the Israeli border crossing, to ensure the materials are not diverted for Hamas military purposes.

Raed Fattouh, the Palestinian Authority coordinator for goods imports to Gaza, said 75 trucks of cement, aggregates and metal supplies were entering Gaza -- double the daily average in 2013.

In a small but significant initial step toward boosting Gaza's wounded economy, the Israeli army said in the coming weeks it would permit Gaza farmers to sell produce to the West Bank for the first time since Hamas took over Gaza in 2007.

The export ban was one of the most painful restrictions on Gaza, because the West Bank used to be the tiny coastal territory's main export market.

In a sign of growing international support for the Palestinians, Ban met with ministers of the new Palestinian unity government in Gaza. Israel has denounced the Palestinian government because it is backed by Hamas, but Western governments have signaled a recent willingness to work with it.

Later, Ban also visited southern Israeli communities that have been battered by years of Gaza rocket fire and consoled the family of a 4-year-old boy killed during the war. The military also gave him a tour of the one of the underground tunnels that Hamas built to attack Israeli civilians -- the discovery of which prompted Israel's ground invasion in Gaza.

"I was shocked and alarmed by the underground tunnels," he said afterward. "No one should live under constant threat or fear of these rockets or the penetrating underground tunnels."

Ban's visit came amid fresh waves of criticism of Israeli policies as Britain's parliament voted Monday to symbolically recognize an independent Palestinian state. British legislators voted 274-12 in support of a motion calling on the government to "recognize the state of Palestine alongside the state of Israel."

Prime Minister David Cameron and other government leaders abstained, and more than half of the 650 House of Commons members did not vote. But the motion had support from both government and opposition lawmakers. Labour Party legislator Jack Straw, a former foreign minister, explicitly described the motion as a challenge to the government of Israeli Prime Minister Benjamin Netanyahu. "The only thing the Israeli government in my view, under the present demeanor of Netanyahu, understands is pressure," Straw said.

The vote should have no tangible effect on British foreign policy. But Britain's ambassador to Israel warned it symbolizes a trend that should worry the Jewish state.

"I think (Israel) is right to be concerned about what it signifies in terms of the direction of public opinion," Ambassador Matthew Gould said, in an interview on Israel Radio.

Earlier this month, Sweden's new Prime Minister Stefan Lofven said his government would also recognize the state of Palestine.

Ban's visit also coincided with the 20th anniversary of Palestinian leader Yasser Arafat and Israeli leaders Yitzhak Rabin and Shimon Peres receiving the Nobel Peace Prize for launching the Oslo peace process.

More than two decades later, Mideast peace remains elusive.

Suspected Israeli vandals set fire to a mosque and left Hebrew graffiti on Tuesday in the West Bank village of Aqraba.

The mosque's carpet was scorched, walls had burn marks, and holy books were covered in soot. The graffiti referenced the name of a late American-Israeli ultranationalist rabbi, a nearby Jewish settlement, and included the words "price tag," a slogan for assaults carried out by Jewish extremists in response to Palestinian or Israeli actions against them.

Israeli police said they were investigating.