Libyan leader Muammar Gaddafi's family arrived on Monday in Algeria, the official APS news agency quoted an Algerian Foreign Ministry statement as saying.

From left to right: Gaddafi's wife Safia, his son Hannibal, his son Mohammad and his daughter Aisha

Gaddafi's wife Safia, his daughter Aisha and two sons Hannibal and Mohammed, and their grandchildren, entered Algeria at 08:45 a.m. local time (0745 GMT) through the Algerian-Libyan border, the statement said.

Algerian officials allowed Gaddafi's relatives to enter the country via the Tinalcom crossing point in Illizi province on the southeast border, Algeria's Arabic daily Echorouk said on its website.

Algeria's UN ambassador Mourad Benmehidi said Gaddafi's family were received on humanitarian grounds, BBC reported.

Benmehidi said he relayed the news to Secretary-General Ban Ki-moon earlier Monday, saying that "we made sure the international community has been informed".

The Libyan convoy, comprising seven cars with 31 people on board, had been waited for 12 hours by the crossing point before being authorized to enter Algeria, Echorouk said.

The health condition of Aisha Gaddafi, who is pregnant in her 9th month, prompted Algeria to let in the convoy in accordance with international treaties, the report noted.

"This would be an act of aggression against the Libyan people and against the wishes of the Libyan people," NTC spokesman Mahmoud Shamman said.

"We will use all legal means to seek the return of these criminals and to bring them to justice in Libya," Shamman said.

Gaddafi's whereabouts are still unknown, BBC reported.