Nigeria’s President Goodluck Jonathan wants the government to borrow $1bn (£580m) to strengthen the military’s capability to fight militant Islamists.
Mr Jonathan wrote to parliament, asking for the expenditure to be approved.
Nigeria has a military budget of about $6bn a year but large sums are lost to corruption, critics say.
Mr Jonathan has faced intense criticism over the government’s failure to curb the increasingly brutal insurgency waged by the Boko Haram group.
The Islamist group caused international outrage in April when it abducted more than 200 schoolgirls in its heartland of north-eastern Nigeria.
In the letter to the Senate and House of Representatives, Mr Jonathan said he wanted to borrow the extra money as part of a “government-to-government arrangement”.
He did not specify which country he was looking at making a deal with.
Mr Jonathan said there was an “urgent need” to upgrade the equipment, training and logistics of the armed forces and security services to help them confront the “serious threat” posed by Boko Haram.
“For this reason, I seek the concurrence of the National Assembly for external borrowing of not more than $1bn,” he said.
Nigeria’s military is receiving help from the US, UK, China, France and Israel to secure the release of the schoolgirls.
Rights groups have repeatedly accused the military of carrying out widespread abuses against civilians, as it tries to hunt down insurgents.
Mr Jonathan sent more troops to the north-east last year after declaring a state of emergency in Borno, Yobe and Adamawa, the three states worst-affected by the insurgency.
However, Boko Haram has stepped up attacks since then.
New York-based Human Rights Watch says more than 2,000 civilians have been killed in Nigeria this year by Boko Haram.
The deaths occurred in around 95 separate attacks in more than 70 towns and villages in the north-east, where Boko Haram launched its insurgency in 2009.
Source: BBC