Cameroon sent warplanes and elite troops from its Rapid Intervention Battalion to stop the fighters after two attacks in Kolofata, close to the Nigerian border, said a regional police source.
Another source close to the local police force, who asked to remain anonymous, said Boko Haram had "kidnapped many people," adding: "There was the sultan, the wife of the deputy prime minster and several police officers".
Four civilians and two police officers were killed in the attacks on the residence of Amadou Ali, the deputy prime minster in charge of parliamentary relations, and the sultan of Kolofata, Seiny Boukar Lamine, said the source.
A source close to the sultan's family told AFP that "four people, including the younger brother of the sultan were killed, (while) he, his spouse and children were kidnapped".
The two attacks were carried out simultaneously at around 05:00 am (0400 GMT), said the source on condition of anonymity.
Another police officer said fighter planes were deployed to Kolofata early on Sunday morning and "there was shelling in the area" after the attacks, without giving further details.
The Nigeria-based Islamist group Boko Haram has stepped up raids into northern Cameroon, murdering and stealing with impunity despite military efforts to clamp down on its insurgency.
On Thursday evening, two Cameroonian soldier were killed as they tried to defend a local village from fighters.
Cameroon, like other west African countries, has beefed up its operations against Boko Haram since the kidnapping of more than 200 Nigerian schoolgirls over three months ago sparked an international outcry.
Also today, at least five people were killed in two attacks on Nigeria's largest northern city, Kano, by suspected militants from the Islamist group.
One attack targeted a Catholic church in a mainly Christian area of the city, when an improvised bomb was thrown into the building shortly after mass, the police said.
In another, a female suicide bomber killed herself and injured five police officers when she blew herself up outside a university in Kano, a police spokesman added.
Boko Haram has killed thousands of people, including more than 2,000 civilians this year, since they started a bloody insurgency to establish an Islamic state in the mainly Muslim north of Nigeria in 2009.