ABUJA // The Philippines said it would extend a ban on sending workers to Nigeria after Christmas Day bombings in left 40 people dead.
The two-year-old ban was to have been lifted by Sunday to allow the movement of thousands of Filipinos seeking to work in Nigeria's booming energy sector.
But the wave of bombings has raised fresh security fears, and the ban will now remain in place for at least three more months, the foreign department said in a statement.
Nigerian Christians have promised to defend themselves after a string of attacks blamed on Islamists as the bombing of an Arabic school raised fears of reprisals.
Police said attackers threw a "low-capacity" bomb into an Arabic school in a drive-by attack in Nigeria's mainly Christian south, wounding six children and an adult on Tuesday evening. Nobody has claimed responsibility.
The attack followed Christmas Day bombings blamed on the Islamist Boko Haram group that killed 40 people in several towns - the deadliest an explosion outside a Catholic church near the capital Abuja.
The president of the Christian Association of Nigeria, Reverend Ayo Oritsejafor, urged followers on Wednesday not to take revenge but said they should defend themselves, their property and their places of worship "any way they can".
"The consensus is that the Christian community nationwide will be left with no other option than to respond appropriately if there are any further attacks on our members, churches and property," Mr Oritsejafor said.
Mr Jonathan urged Nigerians not to shield the culprits.
"The terrorists are human beings, they are not spirits. They live with us, they dine with us. So we know them, people know them. And as long as Nigerians are committed to exposing them, we (will) get over this ugly situation."
Nigerian leaders have been seeking to calm tensions amid fears the Christmas attacks could set off sectarian clashes. The country is roughly divided between a mainly Muslim north and predominately Christian south.
It was not clear who was behind the bomb attack on the Arabic school in Delta state in the oil-producing Niger Delta region.
While scores of explosions have hit the Delta region in recent years, they have mainly targeted oil installations and the attacks have not been of a sectarian character.
Christian leaders urged the government and intelligence authorities to take action against spiralling violence blamed on Boko Haram, and Oritsejafor labelled the attacks "a declaration of war on Christians and Nigeria as an entity".
He said Christians should protect themselves "any way they can".
Also on Wednesday, a coalition of Nigerian Pentecostal churches said they would defend themselves if the authorities failed to do so, though an official stressed they were not advocating taking up arms.
"In the year 2012, if these unprovoked attacks continue and Christians remain unprotected by the security agencies, then we will have no choice but to defend our lives and property," the Pentecostal Fellowship of Nigeria said.
Nigeria's top Muslim spiritual leader met Mr Jonathan over the attacks on Tuesday, stating afterwards that the violence did not signal a religious conflict.