ZONKWA, Nigeria -- Corpses were loaded onto a truck as women covered their noses to block the smell of decay while fleeing this town in northern Nigeria Thursday, as government officials said next week's gubernatorial elections could not go ahead here because of the violence.

Witnesses say hundreds were killed in the town of Zonkwa alone following Saturday's election that unleashed waves of killings in communities across Nigeria's mostly Muslim north after the Christian president won the vote.

Authorities have been fearful of releasing a death toll for fears of sparking more fighting but an Associated Press tour of rural eastern Kaduna state with military leaders Thursday showed violence far beyond what federal authorities seem willing to acknowledge.

In a town near Zonkwa, children raised their hands above their heads as a military convoy carrying soldiers passed, fearful of being shot at by the machine guns mounted on the back. One broken cinderblock wall in the area bore a single word in white paint: War.

Attahiru Jega, chief of Nigeria's Independent Election Commission, announced Thursday that polls could not go ahead as scheduled here in Kaduna nor in the neighboring state of Bauchi because of security concerns, and that the votes in those states will be delayed by two days.

Jega said officials hoped that the delay "will allow further cooling of tempers and for the security situation in those states to continue to improve."

The announcement came just hours after President Goodluck Jonathan vowed in a televised address to the nation that the elections for state governors would be held in 31 of Nigeria's 36 states. Polls in the other five states already had been postponed ahead of the presidential election that sparked deadly violence, despite being considered the most successful since Nigeria became a democracy 12 years ago.

Muslim rioters burned homes, churches and police stations after results showed that Jonathan had beaten his closest Muslim opponent Muhammadu Buhari. Reprisal attacks by Christians began almost immediately.

Ahmed Mohammed Auwal, 23, who is serving as an election official in Zonkwa, said the violence began Monday afternoon after initial election results showed Jonathan ahead. Auwal said he was in the market when townspeople stopped a suspicious truck. The violence started shortly after, spreading through the town. The religious identities of the victims were not immediately known.

"Politics to religion, that's the truth," Auwal said.

Many northerners wanted the country's ruling party to nominate a Muslim candidate this year because Jonathan -- a Christian from the south -- had only taken power because the Muslim elected leader died before finishing his term. However, Jonathan prevailed in the ruling party's primary and became its candidate for president.

Charred corpses bearing machete wounds lay on the highways outside the town of Kaduna in the state bearing the same name. And in Bauchi, an angry mob set ablaze a lodge where young volunteers were staying, killing at least four recent college graduates.

"One way of immortalizing them is to ensure that we complete the remaining election successfully and not to succumb to the designs of people who want to scuttle our collective aspiration for a strong, united and democratic Nigeria," Jega said.

Nigeria has a long history of violent and rigged polls since it abandoned a revolving door of military rulers and embraced democracy. However, observers largely said Saturday's presidential election appeared to be fair, and the U.S. State Department said it was a significant improvement over the last poll in 2007.

The nation of 150 million people is divided between the Christian-dominated south and the Muslim north. A dozen states across Nigeria's north have Islamic Shariah law in place, though the area remains under the control of secular state governments.

Thousands have been killed in religious violence across Nigeria in the past decade. In Kaduna alone, more than 2,000 died as the government moved to enact Islamic Shariah law in 2000. In 2002, rioting over a newspaper article suggesting the Prophet Muhammad would have married a Miss World pageant contestant killed dozens here. But the roots of the sectarian conflict across the north often have more to do with struggles for political and economic dominance.