|Last year explosions rocked an area near where independence celebrations were being held, killing 12 people [AFP]
Nigeria has marked 51 years of independence in a low-key ceremony, prompted by security fears that followed a series of deadly blasts across Africa's most populous nation.
In a broadcast to the nation on Saturday, Goodluck Jonathan, the president, pledged to secure the country, saying his administration "will spare no effort in buildng peace, and securing our homeland against internal threats and infiltration by violent groups from outside our borders".
Massive security was deployed in the capital, Abuja, as Jonathan, dignitaries and foreign diplomats watched soldiers parade in a ceremony at the presidential villa.
Nigeria typically holds memorial ceremonies at the capital's Eagle Square parade ground, open to the public, but authorities moved the event to the secure villa amid fears that the Muslim group known as Boko Haram could carry out fresh attacks.
The group has claimed responsibility for an August 26 deadly bombing of UN headquarters in Abuja, and there has been mounting speculation over it has formed links with outside groups such as al-Qaeda's north African branch.
The nation faces other security threats as well. Last year, the main armed group in the country's oil-producing southern delta claimed responsibility for a dual car bombing outside the capital's Independence Day celebration that killed at least 12 people and wounded dozens more.
"We condemn all acts of violence and declare that such acts of mindless savagery shall not be allowed to define our country. We will not be deterred. Our resolve is strong," Jonathan said in his speech.
He said he had put in place a new national security strategy, but did not provide details.
At the end of the ceremony the president took a dove into his hands and threw it into the air, as other birds released from a cage flew into the sky.
As the television broadcast ended, the state-run broadcaster aired a commercial showing ambulances and the aftermath of bombings, asking mothers to stop the "wanton killing of innocent people".
"Nigeria is not at war," the female announcer said. "It is a country of peaceful people.''
Nigeria gained its independence from Britain in 1960, and struggled for decades under its military rulers, with poverty and endemic corruption. The problems persisted after Nigeria became an uneasy democracy in 1999.