A construction worker, who insisted on anonymity because he is not allowed to speak to press, said the Nigerian household staff members at the residence were left unharmed.
The attackers came from the back of building, as security guarded the front, he said.
Authorities say one British citizen, one Greek, one Italian, three Lebanese and one Filipino were abducted Saturday evening.
No group immediately claimed responsibility for the abductions, though Nigeria's predominantly Muslim north has been under attack by the radical Islamic sect known as Boko Haram.
Boko Haram, whose name means "Western education is sacrilege" in the Hausa language of Nigeria's north, has been blamed for other foreign kidnappings over the past year.