EUROPEAN Union election observers said on Monday at least 21 people were killed during Nigeria's regional elections, which were marked by intimidation, violence and a low turnout. Nigerians voted for state governors in 28 of 36 states on Saturday. Results were still expected from several states on Monday, including northeastern Adamawa, a conservative and Muslim state, which could elect its first female governor. Barry Andrews, European Union Observer Mission Nigeria chief observer told a news conference that Lagos, which re-elected the ruling party's governor, was among several southern and central states that witnessed poll-related violence. "Polling on election day was again disrupted…