The United States has threatened "consequences" as Palestinians step up efforts for statehood demanding accession to almost a dozen international bodies and conventions.

The threat came after Palestinian President Mahmoud Abbas signed the documents on Thursday to join the Universal Postal Union, a UN agency that coordinates international postage, and 10 international protocols and conventions.

The move infuriated the US, Israel's staunch ally, with a State Department official claiming that the Palestinian efforts to join international institutions were “premature” and “counterproductive.”

"We are currently reviewing possible consequences of the Palestinians’ recent actions," the official said in a statement published by the Times of Israel on Sunday.

In November 2012, the UN General Assembly upgraded Palestine’s status from “non-member observer entity” to “non-member observer state” despite strong opposition from Israel.

Since then, the Palestinians have joined dozens of international or organizations and agreements, among them the International Criminal Court, as part of a campaign to garner support for the recognition of their homeland as a sovereign state.

Washington has asked the Palestinians not to join international agencies, citing laws dating to the early 1990s that require the US government to cut off funding to any UN organization that grants the Palestinians full membership.

Abbas, however, said a Palestinian agreement with the US not to join international bodies was conditioned on the US not ending aid payments, not moving its embassy to Jerusalem al-Quds and not changing the status of the Palestine Liberation Organization mission in Washington.

The US withdrew some funding for UNESCO after the Palestinians joined the cultural and education organization back in 2011. It also pulled out of the agency altogether in 2017.

Most recently, Washington cut funds to the UN Palestinian refugee agency UNRWA.

The US-Palestine ties deteriorated last December when President Donald Trump recognized Jerusalem al-Quds as the “capital” of Israel.

The American embassy was also relocated from Tel Aviv to the ancient city in May, sparking angry reactions from Palestinians and severe criticism from the international community.

At that time, Abbas formally declared that Palestinians would no longer accept the US as a mediator to resolve the conflict because Washington was “completely biased” towards Tel Aviv.