UN chief Antonio Guterres on Wednesday made his first visit to Gaza since taking office, as international concern grows over electricity shortages and deteriorating humanitarian conditions in the Palestinian territory.

Hamas, the Islamist movement that runs the Gaza Strip, welcomed the trip, calling it an "important visit," but small demonstrations also occurred.

At one protest, around 25 people held a fake coffin with a sign that said "Welcome to the largest prison in the world".

Dozens of people also demonstrated as Guterres's convoy crossed the border with Israel into Gaza, calling for action in support of Palestinian prisoners held by Israel.

Guterres, who held talks with Israeli and Palestinian leaders in Jerusalem and Ramallah on Monday and Tuesday, was to visit a school in the strip run by the UN agency for Palestinian refugees, UNRWA.

Hamas called on Guterres to make "all efforts to lift the siege on the strip and end the suffering for two million Palestinians living in the largest prison in the world."

The Gaza Strip has been under an Israeli blockade for a decade, while its sole crossing with Egypt has also been largely closed in recent years.

At least 70 percent of Gazans are dependent upon international aid. UNRWA plays a major role in the strip, with the same percentage of the population classified as refugees.

Palestinian militants in Gaza and Israel have fought three wars since 2008, and Israel says the blockade is necessary to keep Hamas from obtaining weapons or materials that could be used to make them.

The blockade also serves to isolate the Islamist movement.

UN officials have however called for the blockade to be lifted, saying the enclave is fast becoming unliveable, with sparse electricity and a lack of clean water.

Before crossing into the Gaza Strip, Israeli officials gave Guterres a tour of the Gaza border area and he was shown a tunnel crossing from the Gaza Strip into Israel.

Such tunnels, used by Hamas for attacks in the past, are a major concern for Israel.

Guterres, who took office at the start of the year, was later due to give a speech in Tel Aviv before departing following his three-day visit.

source: AFP