A Tunisian border guard was killed in a shootout with extremist militants on the border with Algeria, officials said Monday, in an attack claimed by the North African country’s main Takfiri group.

A Tunisian border guard was killed in a shootout with extremist militants on the border with Algeria, officials said Monday, in an attack claimed by the North African country's main Takfiri group.

Finance Minister Slim Chaker said one guard was killed and three others wounded when they were "attacked close to the Bouchebka border post" late Sunday.

"We are taking measures to transport (the wounded) to a military hospital as soon as possible," he told Mosaique FM radio, adding two guards were in a serious condition.

Ridha Ennasri, president of the union of border guards, confirmed to AFP that a border guard was killed in "a terrorist attack".

The shooting was claimed by the Okba Ibn Nafaa Brigades, an Al-Qaeda-linked militant organization that has claimed a string of attacks in Tunisia.

In a message circulated on Takfiri forums the group said it had "ambushed" the guards.

The killing comes days after a Tunisian policeman was shot dead by two assailants on a motorbike in the coastal resort of Sousse.

Authorities have been unable to say whether that killing was carried out by insurgents and an investigation is ongoing.

In June, a Takfiri gunman killed 30 Britons and eight other foreign tourists on a beach in Sousse in an attack claimed by the Takfiri group, ISIL (so-called Islamic State in Iraq and Levant).

Tunisia has been under a state of emergency since that massacre, which followed an attack by gunmen on the Bardo museum in the capital Tunis that killed 21 foreign tourists and a policeman in March.

Extra troops have been posted at tourist sites since the beach killings.