JOHANNESBURG, South Africa - Nigerian President Goodluck Jonathan blamed Boko Haram for an explosion that killed scores of people Monday at a bus station outside his nation's capital, calling the Islamic militant group an "unnecessary distraction" and a temporary problem.

Jonathan, whose leadership has been under intense pressure over his failure to curb the rebellion of Boko Haram in the north of the country, called on Nigerians to be more vigilant about terrorist attacks.

Police confirmed that at least 71 people were killed and 124 injured in the early-morning blast in Abuja. But some local media suggested the death toll could be almost 90.

No group immediately claimed responsibility for the explosion; however, it bore the hallmarks of previous attacks by Boko Haram, which has twice launched suicide bombings in the capital.

The majority of Boko Haram's attacks have been carried out in northern Nigeria. The group opposes a Western lifestyle and secular education and aims to impose Islamic law across the country, which is divided between a mostly Muslim north and predominantly Christian south.

Nigerians tweeted photographs of people who were killed in Monday's blast under the hash tag NotJustNumbers. There were also appeals for blood donations.

Officials offered different accounts of what happened. Nigeria's National Emergency Management Agency reported that the bomb was concealed in a vehicle, but an official from the National Security and Defense Corps said it was believed that the bomb was buried at the bus station, the Associated Press reported.

The Nigerian Vanguard newspaper reported that four people drove a car into the Nyanya bus station and fled, leaving the vehicle, which exploded soon after.