Awwal 29, 1432 H/March 4, 2011, SPA -- A bomb has killed up to 13 people at an election rally in central Nigeria, news reports said Friday. According to dpa, the bomb was thrown into a crowd of supporters of the ruling People's Democratic Party in the central town of Suleja late Thursday, The Sun daily reported on its website. Around 20 people were seriously injured, the report said. One suspect has been arrested. Several thousand people had gathered in a school courtyard in support of the ruling party ahead of April's presidential elections, The Guardian newspaper said. President Goodluck Jonathan ordered a tightening of security measures around his campaign, and condemned the attack, a statement said.