The United Nations General Assembly has agreed to recognise a Palestinian state, despite the UK abstaining in the vote and fierce opposition from the United States.
William Hague was under pressure to back the historic move in New York but said Britain could only support the resolution if the Palestinians gave a commitment to an immediate and unconditional return to the negotiating table with Israel.
The UK also required an assurance that the Palestinians would not seek to extend the jurisdiction of the International Criminal Court (ICC) over the Occupied Territories.
Mr Hague said: "We continue to believe that the prospects for a swift return to negotiations on a two state solution - the only way to create a Palestinian state on the ground - would be greater today if President (Mahmoud) Abbas had been able to give the assurances we suggested, and without which we were unable to vote in favour of the resolution.
"In particular, we called on President Abbas to set out a willingness to return to negotiations without preconditions, and to signal that the Palestinians would not immediately seek action in the International Criminal Court, which would be likely to make a return to negotiations impossible.
"We sought these assurances because they would help create the strongest possible foundation for a return to talks, if combined with action by Israel and support from the international community, after a long and painful period for both parties in the absence of negotiations. This was the guiding principle behind our vote."
The resolution to upgrade the Palestinians' status was approved by 138-9 on the General Assembly, which is dominated by countries sympathetic to the Palestinian cause, with 41 abstentions.
The Israelis have already said they will not return to negotiations following the vote, arguing that it would undermine efforts to secure a Middle East peace settlement.
Mr Hague added: "In the absence of these assurances from President Abbas, the UK abstained on the vote, in accordance with the approach I set out in the House of Commons this week.
"Nonetheless, we will redouble our efforts to restart the peace process, and will continue our strong support for President Abbas, the Palestinian Authority, and a two state solution."