Police arrested Zimbabwe's opposition leader Morgan Tsvangirai in an overnight raid on his home ahead of a mass march called for Wednesday that has been banned by authorities, his opposition group said. Nelson Chamisa, spokesman for the opposition Movement for Democratic Change, said police seized Tsvangirai around 4 a.m. (0200 GMT) at his home in northern Harare. The opposition vowed to go ahead with the march despite the ban by police on security grounds, the Associated Press reported. Chamisa said lawyers were at the Harare central police station trying to secure Tsvangirai's release. No charges were immediately given, he said.