TAIPEI, Nov 20 (AFP) - Security for Taiwan President Ma Ying-jeou was beefed up after a man was caught taking an air gun to a political rally the leader attended earlier this week, his office said Friday.

"Security protection for the president has been enhanced following the incident," said an official at the presidential office.

A 19-year-old man was fined 3,000 Taiwan dollars (90 US dollars) for disrupting social order after he was found taking an air gun to a rally where Ma was present in southern Taiwan.

The man claimed he had no political affiliation and that he accidentally brought the toy gun with him.

The incident has put the presidential security team on heightened alert as Ma is now touring the island to canvass support for his Kuomintang party in the run-up to regional elections next month.

Local reports said more than 200 police were on duty for Ma at a campaign event on Thursday while his bodyguards formed a "human shield" by tightly surrounding him when he was greeting voters from an open-top vehicle.

Ma's predecessor Chen Shui-bian was lightly injured in an election-eve shooting in 2004 but his opponents alleged that the incident was staged to help him win re-election.