The Super Eagles face Liberia in the first leg of the final round qualifier on September 8, but will test themselves against Niger in a friendly first on August 15.
On Sunday, 23 of the 26 players called up by Stephen Keshi reported to camp.
The only absentees were the Sunshine Stars trio of Godfrey Oboabona, Izu Azuka and goalkeeper Moses Ocheje, who were in action for their club in the CAF Champions League game against Algeria's ASO Chlef.
Warri Wolves goalkeeper Chigozie Agbim, who captains the side in the absence of the foreign legion, led his assistant Azubuike Egwueke also of Wolves to the camp early enough along with all other invited players.
“We are here again, happy to be reunited but most importantly its serious business as we want to qualify for the Nations Cup and the World Cup at all cost,” he said.
The team will commence training at the Practice Pitch of the Abuja National Stadium on Monday evening to allow for the arrival of all the players.
FULL SQUAD OF INVITED PLAYERS:
GOALKEEPERS: Chigozie Agbim (Warri Wolves), Daniel Akpeyi (Heartland FC), Moses Ocheje (Sunshine Stars)
DEFENDERS: Azubuike Egwuekwe (Warri Wolves), Papa Idris (Kano Pillars), Juwon Oshaniwa (Sharks FC), Godfrey Oboabona (Sunshine Stars), Ezekiel Henry (Rising Stars), Francis Benjamin (Heartland FC), Umar Zango (Kano Pillars), Osuchukwu Ogonna (Enugu Rangers), Kwambe Solomon (Sunshine Stars)
MIDFIELDERS/FORWARDS: Ejike Uzoenyi (Enugu Rangers), Sunday Mba (Warri Wolves), Reuben Gabriel (Kano Pillars), Izu Azuka (Sunshine Stars), Uche Kalu (Enyimba FC), Henry Uche (Enyimba FC), Obinna Nwachukwu (Heartland FC), Christian Ofili (ABS FC), Solomon Jabason (Akwa United), Kabiru Umar (Heartland FC), Chibuzor Onyekwelu (FAME FC), Sanusi Sani (Gombe United), Sibi Gwar (Niger Tornadoes), Philip Asuquo (3SC).