Palestinians have accused Israel and the United States of inaugurating a "fake" archaeology project in occupied East Jerusalem.
The opening on Sunday of what organisers said was an ancient pilgrimage road runs underneath a Palestinian neighbourhood in the territory that the Palestinians seek as the capital of any future state. Far-right Israelis and settlers say that it was a road that led to the Second Jewish temple 2,000 years ago.
US ambassador to Israel David Friedman and Middle East adviser Jason Greenblatt attended the ceremony next to the Old City, located in occupied East Jerusalem, that hosts the Haram Al Sharif compound, the sensitive holy site controlled by a Jordanian-Palestinian waqf, or Islamic trust.
Saeb Erekat, the chief Palestinian negotiator, said he believed the tunnel was a project being used by Israeli right-wingers to further Israel's claim on east Jerusalem and advance settlement growth there.
"It has nothing to do with religion, it is fake," he told Agence France-Presse in Ramallah in the occupied West Bank.
"It's a settlement project. It's based on a lie that has nothing to do with history", he said.
"This is a disgrace to any diplomat, to undermine the two-state solution, to undermine the fact that there will never be peace without East Jerusalem being the capital of Palestine."
Palestinians and several Israeli NGOs allege that Israeli authorities are using archaeology and questionable digging methods as a pretext to deepen Israel's control over the city.
One of the organisations, Peace Now, also says cracks emerged in several houses in Silwan after the digging began.
The other, Emek Shaveh, said "the use of archaeology by Israel and the settlers as a political tool is a part of a strategy to shape the historic city and unilaterally entrench Israeli sovereignty over ancient Jerusalem."
Jordan, custodian of Muslim holy sites in Jerusalem, said "Israeli efforts to Judaise the Holy City … risk further inflaming tension".
The attendance of Mr Greenblatt and Mr Friedman was a further break with decades of protocol in the disputed city by US President Donald Trump's administration.
They described the archaeological project as historic and further testament to the ancient Jewish presence in Jerusalem.
Israeli settlements in East Jerusalem and the West Bank are viewed as illegal under international law and major obstacles to peace since they are located on land the Palestinians see as part of their future state.