SIPA members, together with NATO and EUFOR troops, raided several houses in Pale to collect additional information on the network supporting Karadzic.
Lukac did not reveal the names of the arrested person or those brought in for questioning, but he said that they were being interviewed.
NATO troops this morning raided the house of retired police commander Jovan Skobo, with the search lasting until early in the afternoon.
"Mr Skobo is believed to be linked to the support network of Radovan Karadzic that allows him to remain at large," said Derek Chappel, a NATO spokesman in Sarajevo.
Chappel added that NATO troops seized certain materials in Skobo's house, but he would not give more details.
SIPA members, with the support and protection of EUFOR troops, also raided the houses of local business people Radomir Kojic and Radislav Ilic, who are suspected to helping fugitives from the Hague tribunal.
Although NATO doubts that Radovan Karadzic and Ratko Mladic are in Bosnia-Herzegovina, it is a fact that there are people who are helping them, Chappel said, adding that it was NATO's goal to thwart the activities of those people.
The NATO headquarters in Sarajevo today called on all with information on fugitives from the Hague tribunal to contact the headquarters. It recalled that a reward of 4.1 million euros is offered for information leading to the arrest of Radovan Karadzic, Ratko Mladic, Vladimir Djordjevic, Goran Hadzic, Stojan Zupljanin and Zdravko Tolimir, whose arrest and transfer the Hague tribunal has been demanding for years.