Somalia's semi-autonomous Puntland region has accused Ethiopia of sending secret agents on a cross-border undercover operation in its territory.

The secret forces reportedly carried out a night raid in the central Somali town of Galkayp on Friday, assassinating two people.

Puntland Security Minister, Abdullahi Said Samatar told the BBC that the forces must have crossed over from Ethiopia's Somali region, also known as the 'Ogaden', where rebels are fighting the government.

"Our relationship with Ethiopia has always been good, but we cannot accept security forces intervening in this way," Samatar said, adding that the Somali government had already sent the other country a written objection.

Press TV correspondent in Somalia said that another person was also kidnapped in the incident.

The rebels in the Ogaden have been seeking independence for Ethiopia's Somali-speaking population since 1984.

Puntland has enjoyed good relations with Addis Ababa since it announced its semi-autonomous status in 1998 -- seven years after the collapse of the central Somali government.

Earlier in January, after a two-year occupation, the 3,000-strong Ethiopian forces finally withdrew from the Horn of African nation, following a deadly insurgents' war waged on both Ethiopian and Somali government forces.

However, since withdrawing, the US-backed Ethiopians have maintained a strong presence along the Somali border.