Tony Blair will quit his job as a Middle East peace envoy next month, sources close to the former Prime Minister have said.
He is understood to have written to UN secretary-general Ban Ki-Moon to formally tender his resignation as the Quartet on the Middle East's representative, effective once he has completed some outstanding duties.
"He remains fully committed to assisting the international community in its work with Israel and the Palestinians to bring about progress on the two-state solution," said a source.
But he is believed to be frustrated by the "political constraints" of the role.
"Although he did contribute to the political process, the Quartet role has been limited to supporting the Palestinian people on economic development and institution building," the source said, adding he would continue in a less "formal" role.
The Quartet, which consists of the US, European Union, Russia and UN, is trying to broker peace between Israel and Palestine. Mr Blair took office there in 2007, six years after its formation, and was put in charge of helping develop the Palestinian economy and institutions with a view to helping establish a Palestinian state.
According to its website, Blair's office succeeded in helping remove dozens of Israeli checkpoints in the West Bank, easing the movement of workers and Palestinian products to markets.
He also helped boost tourism in the West Bank town of Bethlehem, helped secure thousands of permits for Palestinian laborers to work in Israel and helped engineer a $350 million mobile phone investment in the West Bank, creating thousands of jobs.
Mr Blair, 62, "remains fully committed" to helping bring about a two-state solution, the source added.
Among other things, he will "focus on encouraging Israel to take measures which will dramatically improve the daily lives of Palestinians in Gaza", it is said.
Additional reporting by Associated Press
