At least 61 people have been killed by Israeli attacks on Gaza in the last two days as Israel’s war on the besieged enclave enters its 12 month with little sign of respite for the Palestinian territory.

Israeli air raids killed more than a dozen people overnight into Saturday, hospital and local authorities said, as health workers wrapped up the second phase of an urgent polio vaccination campaign designed to prevent a large-scale outbreak.

Sources told A Jazeera that three women and two children were killed in the east of the Nuseirat refugee camp in central Gaza as a result of Israeli shelling.

Separately, Gaza’s Civil Defence agency said an Israeli air attack targeting a school-turned-shelter for displaced Palestinians killed at least three people. The Civil Defence also said 20 people were wounded in the attack that targeted the Amr Ibn al-Aas School in the Abu Iskandar area of the Sheikh Radwan neighborhood, north of Gaza City.

The Israeli military said it conducted a “precise strike” at the school that targeted fighters “operating inside a Hamas command and control centre… embedded inside a compound that previously served as Amr Ibn al-Aas school”.

‘Relentless attacks’

Al Jazeera’s Tareq Abu Azzoum, reporting from Deir el-Balah in central Gaza, said all of Gaza has been under relentless Israeli strikes since the early hours of this morning, particularly in the north.

“There has been a concentration of attacks in the town of Beit Lahiya, with the Israeli army extensively shelling the area with artillery,” he said.

“There has also been an air attack on an evacuation centre in the Sheikh Radwan neighbourhood of Gaza City. A number of casualties are being reported from the attack.”

In recent months, Israeli forces have struck several schools housing displaced Palestinians, many of them in Gaza City, claiming the strikes targeted Hamas fighters.

Israel’s war on Gaza has so far killed almost 41,000 people, according to the Health Ministry in Gaza. According to the United Nations, most of the dead are women and children.

Pro-Palestine protests in London

Meanwhile, throngs of protesters rallied against Israel’s war on Gaza in central London on Saturday.

Demonstrators shouted slogans and carried banners as they rallied through the capital towards the Israeli embassy in South Kensington.

“Pro-Palestinian protesters have held a rally in London in the week that saw British Foreign Secretary David Lammy say that his country would immediately suspend 30 of the 350 licences to export arms to Israel,” Al Jazeera’s Sonia Gallego said, reporting from London.

“But for people who we have spoken to here, the move is not nearly enough. As Lammy himself has said, this certainly does not go as far as back in 1982, when PM Margaret Thatcher imposed a full arms embargo on Israel over its participation in the Lebanon war.

“However, people here are demanding that more be done. They want all arms exports to end with immediate effect because we are going into nearly 11 months of Israel’s war on Gaza and the situation only seems to be worsening.”

Call for inquiry over killed activist

The UN also called for a “full investigation” into the killing by Israeli forces of American-Turkish activist Aysenur Ezgi Eygi, 26, while protesting against illegal Israeli settlements in Beita, in the occupied West Bank.

“We would want to see a full investigation of the circumstances and that people should be held accountable,” UN spokesman Stephane Dujarric told a news conference, adding that civilians “must be protected at all times”.

Eygi was “shot in the head” while participating in the demonstration on Friday, the UN rights office said.

Her family also called for an inquiry in a statement, saying “her presence in our lives was taken needlessly, unlawfully, and violently by the Israeli military”.