Israeli Defense Minister Avigdor Liebermann on Sunday rejected calls for an inquiry into the killing of at least 15 Palestinians by the military at a demonstration on the Gaza-Israel border on Friday, saying soldiers had done the right thing.

"Israeli soldiers did what was necessary. I think all our soldiers deserve a medal," he told Army Radio.

"As for a commission of inquiry — there won't be one," he added.

Day of mourning

Palestinians declared a national day of mourning on Saturday after the mass protest the day before led to clashes amounting to the bloodiest day in the Gaza Strip since a 2014 war.

More than 1,400 people were also injured during the marches at the territory's border, held to demonstrate for the rights of Palestinian refugees unable to return to their homes in present-day Israel.

Friday's protest, organized largely by Gaza's ruling Hamas group, was the start of what is planned to be a six-week campaign against Israel's treatment of Palestinians.

The campaign is to culminate in a border march on May 15 — the day after the 70th anniversary of Israel's founding — to commemorate the hundreds of thousands of Palestinians uprooted during the 1948 Middle East war surrounding the creation of the Jewish state. The events of that time are called the "nakba," or "catastrophe," by Palestinians.

Read more: Israel's Independence Day is 'Nakba' for Palestinians 

Praise for soldiers

Protests on Saturday were more muted than the previous day, with only small groups of Palestinians throwing stones at various locations along the border fence. Twenty-five people were injured by Israeli fire, according to Gaza's Health Ministry.

Israel's military has said that at least eight of those killed were members of Hamas' militant wing and two others were members of other militant groups in Gaza. Hamas says that five of those killed were its members.

Israeli Prime Minister Benjamin Netanyahu has praised soldiers for allowing the rest of the country to celebrate the Passover holiday safely.

UN motion rejected

However, United Nations chief Antonio Guterres and the EU's top diplomat, Federica Mogherini, have called for an "independent and transparent investigation" into Israel's use of live ammunition.

But a corresponding motion put to the Security Council by Kuwait was rejected by the United States, according to AFP news agency and other media sources.

Fuel has been added to the fire of Palestinians' anger by the announcement that the United States will open a new embassy in Jerusalem around May 14. Palestinians see the city's annexed eastern sector as the capital of their future state.

More than 700,000 Palestinians either fled their homes or were expelled during the 1948 war, with most Gaza residents being descendants of the refugees.

The coastal strip has been subjected to a border blockade by Israel and Egypt since 2007, when the militant Islamic group Hamas took control of the enclave. The closure has worsened economic conditions in the Gaza Strip, which suffers from rising unemployment, high rates of poverty and frequent power shortages.

tj/rc (AFP, dpa, AP)Each evening at 1830 UTC, DW's editors send out a selection of the day's hard news and quality feature journalism. You can sign up to receive it directly here.