The UN Security Council has expressed concern over the two-week violence in Gaza that has claimed more than 450 lives – at least 70 of them civilians.

LIVE UPDATES: Israel launches ground incursion in Gaza Strip

"The members of the Security Council expressed serious concern about the growing number of casualties. The members of the Security Council called for an immediate cessation of hostilities," Rwandan UN Ambassador Eugene Gasana told journalists after an emergency meeting on Sunday.

Jordan demanded the meeting after over 60 Palestinians and 13 Israeli soldiers were killed as Israel shelled Gaza's Shejaia neighborhood and battled militants in the bloodiest fighting in the 13-day offensive, Reuters reported.

"The members of the Security Council called for respect of international humanitarian law including protection of civilians," Gasana added.

UN Secretary-General Ban Ki-moon condemned the killings as an "atrocious action" and called for an immediate end to the fighting, urging Israel to “exercise maximum restraint.”

“Too many innocent people are dying (and) living in constant fear,” he said at news conference in Doha.

Also on Sunday, US President Barack Obama called for an “immediate ceasefire” between Israel and Hamas.

“The situation is intolerable,” Fatah leader Mahmoud Abbas said earlier in a televised speech from the Qatari capital, Doha.

“What the occupation forces did today in Shejaia is a crime against humanity,” Abbas said. “Those who committed it will not go unpunished.”

As the IDF continues the operation in Gaza, Abbas arrived in Qatar on Sunday to discuss a potential ceasefire with Hamas leader Khaled Meshaal and the UN chief.

WARNING: Graphic video of the shelling aftermath in Shejaia

Israel claims that its forces killed at least 10 Palestinian militants who, the IDF say, entered the south of the country from Gaza to carry out an attack.

"A short while ago two terror squads were detected infiltrating through two tunnels from the northern Gaza Strip into Israel," a military spokeswoman told Reuters.

Palestinian health officials said the death toll since July 8 had reached 447, including many civilians, with 12 more bodies recovered from the embattled Shejaia neighborhood where the number of fatalities rose to 72 from Sunday's fighting.

“The Israeli aggression against civilians should be stopped,” said al-Shifa’s hospital administrator.

AFP puts the death toll at 476.

As Israel heavily shelled Gaza's eastern suburb of Shejaia battling the alleged Hamas militants in the bloodiest fighting in the 13-day offensive, officials said 35,000 people fled the fighting in Gaza on Sunday as the artillery bombardment began.

The ambulances and fire trucks moved in to Shejaia at 10:30 GMT after the announcement of a two-hour truce to retrieve the dead and wounded.

Inside the shelled neighborhoods, scores of people lay dead, others were wounded with scenes of entire buildings destroyed. Houses were still ablaze from the IDF onslaught, with corpses burnt almost beyond recognition, with the dead numbering both young and old, including small children.

But in a few hours, the shelling resumed as the IDF announced Hamas had breached the truce and it was responding “accordingly.”

The injured from Shejaia were rushed to Gaza City's central Shifa Hospital. Chaos reigned inside the hospital as wounded children were brought to the overflowing emergency room, forcing the medical staff to treat the wounded in a hallway. Those who could still walk fled to some of the 61 UN shelters with more than 81,000 people from all over Gaza strip taking sanctuary in them, the refugee agency said.

"Shejaia was particularly badly affected with thousands of people reportedly fleeing their homes this morning, as heavy bombardment from Israeli tanks and artillery continued," United Nations Relief and Works Agency said in a statement.

As the Palestinian death toll soared to 438, a spokesman for the Gaza emergency services said more than a third of the victims were women and children.

Israeli Prime Minister Benjamin Netanyahu defended the Israeli actions on Sunday, blaming Hamas for using civilians “as human shields.”

We fired a warning shot at this target in Gaza. In response, these civilians ran to the roof and brought their kids. pic.twitter.com/GNLPhXAtgn — IDF (@IDFSpokesperson) July 20, 2014

“We are carrying out a complex, deep, intensive activity inside the Gaza Strip and there is world support for this... very strong support,” he said ahead of a security cabinet meeting.

Shejaia lies next to the separation barrier between Israel and Gaza, east of Gaza City. Because of its geographical location to the buffer zone, the Israeli army claims that Shejaia is responsible for 8 percent of the rockets launched from Gaza.

WARNING: GRAPHIC VIDEO