Nigerian security forces have killed 14 people as they stormed the hideout of the suspected kidnappers of a Turkish national.

Police say the raid took place  Friday in the oil-rich Rivers State region. Officials say militants in the region have been linked to a string of kidnappings, armed robberies and other violence.

The French news agency (AFP)  says the Turkish national who was abducted had been freed after his captors were paid a ransom.

In another incident, witnesses said Nigerian soldiers shot and killed more than 40 people in the city of Maiduguri, most of them young men. 

The city is a stronghold for the Boko Haram militant group.

Residents of the city say soldiers from Nigeria's Joint Task Force (JTF) carried out the killings during raids on several neighborhoods late Thursday.

A source in the city morgue says that he came to work Friday to find that the bodies of about 40 young men had been dropped off.

Rights groups Amnesty International and Human Rights Watch have accused the JTF of extra-judicial killings as the force tries to crush Boko Haram.  The JTF has denied the allegations.

Boko Haram, a shadowy militant group, wants to impose Islamic law across northern Nigeria and is blamed for the death of more than 1,400 people since 2009. 

Some information for this report was provided by AFP and Reuters.