National security adviser John Bolton defended calling Palestine a "so-called state," saying Wednesday "it is not a state."

Bolton, speaking to reporters in the White House briefing room, said that denying Palestine's statehood isn't counterproductive as the Trump administration prepares to unveil a Mideast peace plan.

"It's not a state now. It does not meet the customary international law test of statehood," he said. "It doesn't control defined boundaries. It doesn't fulfill normal functions of government. There are a whole host of reasons why it's not a state."

"It could become a state, as the president said, but that requires diplomatic negotiations with Israel and others," Bolton continued.

The Palestine Liberation Organization, then led by Yasser Arafat, declared independence in 1988. Since then, 137 United Nations member states extended diplomatic recognition.

Palestinian authorities have controlled some territory in the West Bank and Gaza since the 1994 Oslo Accords, but rival factions — Hamas in Gaza, Fatah in the West Bank — have dominated the territories since 2007.

Bolton, known for his generally hawkish foreign policy views, said there was nothing historically remarkable about U.S. officials denying that Palestine is a state.

"Calling it the so-called state of Palestine defines exactly what it has been, a position that the United States government has pursued uniformly since 1988 when the Palestinian authority declared itself to be the State of Palestine," he said. "We don't recognize it as the State of Palestine, we have consistently across Democratic and Republican administrations opposed the admission of Palestine to the United Nations as a state because it's not a state."