Nabil Abu Rudeineh called it "a continuation of the hostile approach of the American administration toward our Palestinian people and ... contrary to all UN resolutions."
In a statement carried by official Palestinian news agency WAFA late on Wednesday, he said the change was part of US President Donald Trump's plan to "liquidate" the Palestinian cause.
Washington no longer refers to Golan as 'Israel-occupied'
Trump is expected to unveil his long-awaited plan for Israeli-Palestinian peace in the coming months, even though the Palestinian leadership has frozen contact with Washington over Trump's 2017 declaration of Jerusalem as Israel's capital.
Palestinians believe the upcoming plan will be blatantly biased in favour of Israel.
In its latest human rights report published on Wednesday, the United States referred to the Golan Heights as "Israeli-controlled" as opposed to "Israeli-occupied".
Another semantic change that appeared in last year's report showed up again this year, with a section titled "Israel, Golan Heights, West Bank and Gaza," instead of its previous "Israel and the Occupied Territories" heading.
US downgrade of Palestinian mission to take effect Monday
The US State Department insisted the different wording did not mean a change in policy.
Israel occupied the Golan Heights, West Bank, East Jerusalem and the Gaza Strip in the 1967 Six-Day War.
It later annexed the Golan Heights and East Jerusalem in moves never recognised by the international community.
It has withdrawn from the Gaza Strip, but has fought three wars with Palestinian militants there and maintains a blockade of the territory.
Israel's occupation of the West Bank continues.
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