Intelligence and military officials from Pakistan and Afghanistan, which have a history of mutual mistrust, will also meet to discuss the training of police and security forces.
The summit agenda is to include a proposal that Turkey's religious high school system, the Imam-Hatip system, could offer Afghanistan and Pakistan a model to prevent religious fundamentalism.
The meeting comes only days before Barack Obama, the US president, visits Ankara.
A unnamed senior Pakistani official told the Reuters news agency initiatives were under way to begin negotiations with some factions of the Taliban.
"The Turks are playing a behind-the-scenes roll patching up relations between Pakistan and Afghanistan," the official said. "There’s a lot happening behind the scenes that people don’t know about."
"The Turks are among those working on negotiations with the Taliban - not all the Taliban, it's being selectively done."
Earlier this month, Miliband and Ahmet Davutoglu, the Turkish foreign minister, said that without reconciliation between Afghanistan’s factions, no settlement could be achieved.
Ready to try
With 1,700 troops already deployed and a further 1,000 promised, Turkey was ready to try to persuade the Taliban to end the violence and take part in elections, Davutoglu said at the time, without elaborating.
A European Union diplomat in Brussels told Reuters that he saw the meetings in Turkey as preparing the ground for the London conference.
"Clearly there are going to be a lot of contacts among all the players, including the Russians and Turkey, in the run-up to the London conference.
"That's just part of preparing for a big conference like this, that I think everyone now sees as happening at a crucial time."