Turkey views the PYD as an extension of the Kurdistan Workers' Party, or PKK, which has renewed a decades-old insurgency since peace talks collapsed last year. The U.S. also considers the PKK a terrorist group, but both Washington and Moscow support the YPG, which has been among the most effective forces against the Islamic State group.
When Sharapudinov got to Syria, he said, Islamic State was on the rise but did not control much territory. He joined a rebel group called Sabri Jamaat with other fighters from Russia and post-Soviet states. They were based in Al Dana near Aleppo, and Islamic State controlled neighbouring territory.
At one point, Rabadanov had been detained for keeping explosives at his home, according to his father, Suleiban Rabadanov, but had been released shortly afterwards and placed under house arrest instead.
Relatives, neighbours and local officials gave accounts of what happened to the men. The five shared some common threads: They were all from Dagestan, and Russian authorities had reason to deny them travel documents and prevent them from leaving the country. But according to relatives and local officials, in each case the authorities made their passage possible.
He said there were cases over a few years but that it had nothing to do with the Sochi Games. He said the security services did not help anyone leave. "If no measures are being taken against them, according to law, they have same rights as every Russian citizen," he said. "They could get an international passport and leave."
Sharapudinov had his own reasons for leaving Russia. There were tensions between him and the local emir, who was also the commander of the militant group to which he belonged. When Sharapudinov told his mother of the FSB's offer, she tearfully asked him to take it, he said, because she did not want him to be a fugitive any longer.
Mustafa Ali, 39, often tells his children about the beauty of the land they left behind. He was a primary school teacher and a sports trainer in Aleppo until he had to flee three years ago with his wife Suzan, 25, and his two children Sedra, 8, and Hamza, 5. His youngest daughter, Hulya, 2, was born in their adopted city, Istanbul, Turkey.
Dmitry Peskov, spokesman for Russian President Vladimir Putin, told Reuters: "Russian authorities have never cooperated or interacted with terrorists. No interaction with terrorists was possible. Terrorists get annihilated in Russia. It has always been like that, it is like that and it will be in the future."
On the 5th anniversary of the Syrian war, The Associated Press met with five-year-old Syrian children and their parents in Lebanon, Jordan, Turkey, Iraq and Greece. The AP also asked their parents what they would share with their children about the Syria they knew. Some were hesitant, as if reminiscing was a luxury. Some spoke freely. Sadness is the dominant theme.
According to Sharapudinov, the two groups were friendly towards each other. Later, Sabri Jamaat pledged allegiance to Islamic State, though Sharapudinov said that by that time he had quit fighting and left Syria. He declined to say whether he had seen other Dagestani radicals in Syria.
According to Sharapudinov, the intermediary took him to the town of Khasavyurt, where a high-ranking local FSB official was waiting. Though Sharapudinov had been given guarantees about his safety, he remained suspicious, he said. So he took along a pistol and a grenade in his pocket, despite a condition that he should come unarmed.
But life in Istanbul is hard. Mustafa doesn't have a work permit. Every now and then he finds freelance work as a Turkish-Arabic translator and as a real estate agent, mostly for Syrians living in Istanbul. He hopes to take his family to the Netherlands one day, where he says there are fewer refugees than Germany.
The Islamist groups, fighting to establish a Muslim state in the region, were exhausted after years on the run and had failed to score any significant victories against security forces. The authorities were frustrated because the militants - holed up in remote mountain hideouts or protected by sympathisers - still eluded arrest.
Russian authorities deny they ever ran a programme to help militants leave the country. They say militants left of their own volition and without state help. Officials, including FSB director Bortnikov and authorities in the North Caucasus, have blamed the departures on Islamic State recruiters and foreign countries who give radicals safe passage to Syria and elsewhere.
Then from 2013 Islamists began threatening to attack the Sochi Olympics, posting videos of their threats online. An attack would embarrass Putin at an event meant to showcase Russia; Moscow ordered a crackdown.
"They said: 'Go wherever you want, you can even go fight in Syria,'" Sharapudinov told Reuters in December. He recalled that the Olympics came up in the negotiations. "They said something like, 'to let the Olympics pass without incidents.' They didn't conceal they were sending out others as well," he said.Kozak said the government is making a "low-cost investment" to position itself near Raqqa and "message its involvement in the ISIS campaign, to bolster its international credibility." The SDF has not been able to recruit enough Arab fighters, and the Kurds would rather focus on liberating areas in the Raqqa governorate that border Kurdish regions.
In a speech later Monday, Erdogan urged the government to "redefine" terrorism and terrorists so that legal action can be expanded against anyone supporting terrorism - including lawmakers, academics, journalists or activists.
Turkish military-imposed curfews remain in the historic district of the main Kurdish city of Diyarbakir - which is also called Sur - and in Idil, a district in Sirnak province, where Turkish forces are continuing operations against Kurdish militants. Amnesty International says the curfews amount to "collective punishment."
Residents and officials in Dagestan said that once Russian militants arrived in Syria they encouraged others from their home communities to join them. From the village of Berikey, which has a population of 3,000, some 28 people left for areas of the Middle East controlled by Islamic State, according to the local police officer. He said 19 of the 28 were listed in Russia as radicals.
The government, dominated by Assad's Alawite sect of Shiite Islam, controls Damascus, the Alawite heartland along the Mediterranean coast, and other cities and connecting corridors in between. The Kurds run their own affairs in the northeast.
Her mother Doaa dreams of returning and raising Tala in Syria. "We were not rich, but we were not poor. We lived a fine life. God willing, she will live like we once did. We don't want more, or less, than that," she says.
Security and forensic officials work at the site of Sunday's explosion in the busy center of Turkish capital, Ankara Monday, March 14, 2016. The explosion is believed to have been caused by a car bomb that went off close to bus stops. (AP Photo/Burhan Ozbilici)
Despite being under such restriction, Rabadanov was able to leave Russia: He passed through passport control at a Moscow international airport along with his wife and his son in May 2014, his father and the local police officer said. He later turned up in Syria, his father said. Government officials had no comment on Rabadanov.
Just two weeks after the Syrian conflict started, Tala was born in the southern province of Daraa, where the Syrian conflict originated, on March 28, 2011. Her parents, former oil field worker Izhak al-Faouri, 34, and schoolteacher Doaa al-Faouri, 26, fled to Jordan after airstrikes drove them out of their homes in the village of Sheikh Miskeen.
Security and forensic officials work at the site of Sunday's explosion in the busy center of Turkish capital, Ankara Monday, March 14, 2016. The explosion is believed to have been caused by a car bomb that went off close to bus stops. (AP Photo/Burhan Ozbilici)
In this March 6, 2016 photo, Winda Farman Haji, a 5-year-old refugee from a town outside Malikiyah in northeast Syria, poses for a portrait inside the tent she shares with her family at Kawergosk refugee camp in Iraq. Winda was born in a village outside Malikiyah in the Kurdish part of northeastern Syria, where her father Sharif Farman Haji, 44 worked as a lorry driver on the Malikiyah-Qamishly route. They fled August 2012 but their troubles didn