Abuja - Nigerian President Goodluck Jonathan's decision to head to a climate change conference in Brazil as dozens died in sectarian clashes this week has angered allies and opponents.
At least 92 people have been killed in violence between Muslims and Christians in the northern city of Kaduna in the past three days, sparked by suicide bombings of churches on Sunday, thought to be the work of the Islamist sect Boko Haram.
The sect, seen as the number one security threat in Africa's top energy producer, has also stepped up its insurgency in the northeastern heartland, where 40 people were killed in the city of Damaturu in clashes with the military between Monday and Wednesday.
But at the height of the unrest in both cities on Monday, Jonathan flew to a United Nations climate change conference in Rio de Janeiro.
Angered by his decision, members of the lower house of parliament voted on Tuesday to summon Jonathan for an explanation. It is rare for lawmakers to demand an audience with the president.
"It's akin to a head of family leaving his home still consumed by a raging inferno but finding it convenient to attend a village meeting on cleanliness of the village square," said the opposition Congress for Progressive Change, whose candidate Muhammadu Buhari was Jonathan's main rival in April polls.
Information Minister Labaran Maku defended Jonathan's decision.
"The world is now a virtual society, the president can take decisions from anywhere in the world," Maku told Reuters.
"The vice president effectively takes charge of affairs once the president is out of Nigeria and he is in touch with the president on an hourly basis."
Jonathan's political opponents have been keen to make political capital from his failure to deal with the crisis in the north, frequently publishing criticism.
A growing perception of him as a weak president is likely to make it harder for him to push through key campaign pledges, such as improving Nigeria's woeful electricity supplies.
When suicide bombers blew up three churches on Sunday, killing 19 people and sparking riots in which another 52 people lost their lives, local press quoted a statement from his office saying that he was "saddened" by the violence, a response many Nigerians felt was inadequate.
"Does that mean that the climate change conference is more important to the president than the lives and property of Nigerians?" asked Benjamin Aboho, a member of parliament for Jonathan's ruling People's Democratic Party.
The escalating violence has raised fears of a wider sectarian conflict in a country already reeling from months of attacks on government buildings and churches by followers of Boko Haram.
Social networking sites highlighted the anger felt by some Nigerians over Jonathan's absence.
"If this government was for the people of Nigeria, Goodluck Jonathan would not be in Brazil, he'd be in Nigeria sorting out this security mess," Japeth Omujuwa, a Nigerian commentator with 30,000 followers, said on his Twitter feed on Wednesday.
Jonathan said in March that Boko Haram's insurgency would be over by June, antagonising the Islamists, who pledged to prove him wrong and embarrass his government, something they may have achieved this week.