Lebanese army troops patrol the airport road on the southern outskirts of Beirut on Friday, following the kidnapping of two pilots working for Turkish Airlines. (ANWAR AMRO/AFP/Getty Images)

Gunmen abducted two Turkish Airlines pilots as they left Lebanon’s main international airport Friday, Turkish and Lebanese officials said, in an apparent escalation of a string of tit-for-tat kidnappings linked to the war in neighboring Syria.

Turkey urged its citizens to leave the country immediately after the early-morning kidnapping on the road from Beirut’s Rafiq al-Hariri International Airport to the pilots’ hotel on the city’s seafront. A group that claimed responsibility demanded the release of nine Shiite Lebanese hostages held by rebels in Syria in exchange for the men.

Turkey’s support of the Syrian rebels has proved controversial in Lebanon, where the population is deeply divided over the conflict. Last year saw a flurry of kidnappings and threats targeting Syrians, Turks and Persian Gulf nationals in retaliation for the detention of Lebanese Shiites by the predominantly Sunni rebels in Syria as the civil war took on increasingly sectarian undertones.

The pilots with Turkey’s national airline are the highest-profile targets yet. Families of the nine Shiite pilgrims who were abducted in the Syrian province of Aleppo in May of last year denied any role in Friday’s kidnapping. But they have staged protests outside the Turkish Airlines offices in Beirut and the Turkish Embassy to voice their frustration over abortive negotiations to secure the release of their relatives.

The pilots were abducted about 3 a.m., the Lebanese Interior Ministry said. After landing on a Turkish Airlines flight from Istanbul, they were forced out of a minibus carrying crew members about half a mile from the airport, according to local media reports. Eight armed men in two cars intercepted the bus, the Lebanese official National News Agency reported. Other accounts put the number of gunmen at six.

The other crew members were allowed to go free, and the driver was being questioned by police, the ministry said. The airline identified the pilot as Murat Akpinar and his co-pilot as Murat Agca.

“All Lebanese security agencies are on full alert and searching for the kidnapped,” Lebanon’s caretaker prime minister, Najib Mikati, said in a statement. “Abductions are categorically rejected.”

Turkish President Abdullah Gul said he intended to call his Lebanese counterpart to demand the release of the two men. “Lebanon is a hard and a risky place. I hope they will be rescued in full health as soon as possible,” he told the CNN-Turk TV channel.

A little-known group calling itself Zuwar Imam al-Rida issued a statement Friday saying it had carried out the kidnapping, the National News Agency reported. The group said the men would not be released until the Shiite pilgrims are freed.

The pilgrims’ families said they hoped the kidnapping would bring about the release of the nine men still detained in Syria. Two other abductees were released last year after two Turkish nationals were kidnapped in Lebanon by a prominent Shiite clan, which also was demanding the release of one of its clansmen missing in Syria.

“We are against kidnapping. We feel for [the families of the pilots] because we have suffered from kidnapping,” said Haji Hayat Awaili, an organizer of the pilgrimage who speaks for the families. “On the other hand, the last time two Turks were kidnapped, two of our kidnapped were released.”

She said the nine detainees included a 67-year-old in need of medication and accused the Turkish government of “procrastinating.”

“Why is the Turkish government not moving?” she said, adding that the families would launch new protests Monday.