A new outbreak of post-poll rioting in northern Nigeria left many dead overnight, the Red Cross said Tuesday, after President Goodluck Jonathan appealed for unity following his win.

Authorities have not given a death toll for the rioting that began sporadically over the weekend over allegations of vote rigging and quickly spread to some 14 states on Monday. An estimated 15,000 have been displaced.

Deadly riots erupted across Nigeria's north on Monday as results from presidential elections showed incumbent Goodluck Jonathan had won the contest that reflected deep regional tensions.

Results from all of Nigeria's states announced by the electoral commission showed Jonathan had handily beaten his northern rival, ex-military ruler Muhammadu Buhari. The electoral commission was yet to officially declare him the victor.

Rioting and acts of violence which broke out in Nigeria following presidential elections are taking place in areas inhabited by locals, away from the houses of Lebanese expatriates, Lebanon's state-run National News Agency reported Monday.

Riots spread across Nigeria's north on Monday as results from presidential elections showed incumbent Goodluck Jonathan assured of victory in polls that reflected deep regional tensions.

Nigerian officials have decided to postpone Saturday's parliament elections after organizational problems marred the start of the vote, the electoral commission chief announced.

"In order to maintain the integrity of the elections and retain effective overall control of the process, the commission has taken the very difficult but necessary decision to postpone the national assembly elections to Monday, April 4, 2011," Attahiru Jega told journalists.

Senegal has cut diplomatic ties with Iran, accusing it of delivering weapons to separatist rebels in its restive southern Casamance region where 16 soldiers have been killed since the end of December.

A cache of Iranian weapons concealed as building material intercepted in Nigeria in October 2010, was found to be one of several shipments passing through Gambia and destined for the Casamance rebel movement.

Filling stations, churches and mosques were set ablaze in central Nigeria's city of Jos on Saturday after students were wounded when soldiers opened fire to quell a protest overnight, security officials and students said.

Clashes had broken out Friday after three university students were stabbed by motor-cycle riding Muslim villagers outside their hostel.

Amnesty International and Friends of the Earth Tuesday said they had filed an official complaint against Anglo-Dutch firm Shell for shirking responsibility for oil spills in Nigeria and wreaking havoc on the environment.

A joint statement said Shell's operations in the southern oil-rich Niger Delta breached the Organization for Economic Cooperation and Development (OECD)'s guidelines for responsible business.

Soldiers rushed to restore calm to parts of central Nigeria on Tuesday after 13 people were reported killed in an attack on a village and unrest flared in other areas, authorities said.

Central Nigeria has seen a wave of violence in recent weeks, including Christmas Eve bomb blasts and reprisal attacks that killed at least 80 people as well as clashes between Christian and Muslim ethnic groups.