Two protesters have been shot dead in further demonstrators along the Gaza border.
Tuesday's deaths came as Palestinians observed a general strike to mourn 58 killed by Israeli army fire on Monday - the deadliest day in Gaza since a 2014 war.
Organisers said Tuesday would be set aside for funerals, while only dozens of protesters descended on the border with Israel for a fresh day of demonstrations.
Palestinian health officials, who announced the death and injury tolls, said five of the 58 killed on Monday were children, including a baby who died of tear gas inhalation. On Tuesday they announced the further deaths.
The Islamic militant Hamas group, which rules the territory, had initially said mass border protests would continue on Tuesday.
The day marks the 70th anniversary of what Palestinians call their “nakba”, or catastrophe — the uprooting of hundreds of thousands in the Middle East war over Israel’s 1948 creation.
Palestinian President Mahmoud Abbas has declared three days of national mourning over the deaths.
While Palestinians protested on the border on Monday, a few miles away Israel and the US held a festive inauguration ceremony for the new US embassy in contested Jerusalem.
The high toll in Gaza revived international criticism of Israel’s use of lethal force against unarmed protesters, while the opening of the embassy, condemned by Palestinians as blatantly pro-Israel, further dimmed prospects of what President Donald Trump had once touted as plans to negotiate the Middle East “deal of the century”.
The UN Security Council is meeting to discuss the violence, although it is not clear what might come out of the session.
Two UN diplomats said members could not reach unanimous agreement on a proposed statement, circulated by Kuwait, that would have expressed “outrage and sorrow” over the killings and sought an independent investigation.
On Tuesday, Theresa May condemned the deaths as "tragic and extremely concerning", and called for both sides to show restraint.
Speaking at a joint press conference with Turkish President Recep Tayyip Erdoğan who earlier branded the deaths by Israeli army fire a , which the opening of the new US embassy in Jerusalem had "paved the way for", the Prime Minister described the situation as "troubling".
Israel has defended its actions, saying troops were defending its border. It also accused Hamas militants of trying to carry out attacks under the cover of the protests.
The Israeli military said its aircraft had struck 11 “terror targets” in a Hamas military compound a day earlier, and that tanks targeted two Hamas posts.
It said protesters used 10 explosive devices and firebombs against troops and that shots were fired at soldiers positioned along the border.