Forcefully stepping into an explosive Middle East debate, President Barack Obama on Thursday endorsed a key Palestinian demand for the borders of its future state and prodded Israel to accept that it can never have a truly peaceful nation based on "permanent occupation."

Obama's urging that a Palestinian state be based on 1967 borders — before the Six Day War in which Israel occupied East Jerusalem, the West Bank and Gaza — was a significant shift in the U.S. approach. It drew an immediate negative response from Israeli Prime Minister Benjamin Netanyahu, who is to meet with Obama at the White House Friday.

In a statement released late Thursday in Jerusalem, Netanyahu called the 1967 lines "indefensible," saying such a withdrawal would jeopardize Israel's security and leave major West Bank settlements outside Israeli borders, though Obama left room for adjustments reached through negotiations.

At the same time, it was not immediately clear whether Obama's statement on the 1967 borders as the basis for negotiations — something the Palestinians have long sought — would be sufficient to persuade the Palestinians to drop their push for U.N. recognition of their statehood. Obama rejected the Palestinians' unilateral statehood bid Thursday as he sought to underscore U.S. support for Israel notwithstanding the endorsement of the 1967 borders.