Abductions of journalists inside Syria have increased sharply this year as the ravages of the conflict have worsened and the insurgency has turned more jihadist and chaotic, making the country one of the most hostile conflict zones for news gatherers in recent memory, according to news media advocacy organizations, rights workers and veteran correspondents.

Some appear to have been carried out by armed insurgent extremist groups and criminal networks seeking ransom in cash, weapons or both. But others have no declared motive.

Foreign journalists are particular targets, mostly Europeans who have ventured into Syria, usually without the permission of the Syrian government, to cover a conflict now well into its third year. Syrian journalists have been taken, too, as have Syrians working with foreign news organizations.

Foreign reporters were initially welcomed by many insurgents and Syrian civilians, taken for advocates who could publicize grievances against President Bashar al-Assad. Now they are sometimes viewed as interlopers who have no stake in the outcome of the conflict, which has left more than 100,000 people dead.