Danish cartoonist Kurt Westergaard, who inflamed Islamists with his caricatures of the Prophet Mohammad, says he cut short his book tour in Oslo, Norway after being told of a possible threat.

The 76-year-old Westergaard returned from Oslo to Denmark late Monday after Norwegian and Danish security agents warned of a possible plot against him. The official reason given for his early departure was that he was suffering from heart trouble. But Westergaard says he is actually fine.

Westergaard has lived with round-the-clock security since his 12 caricatures of Mohammad were published in the Danish newspaper Jyllands-Posten in 2005. The cartoon that provoked the most ire was one of Mohammad wearing a turban shaped like a bomb with a lit fuse.

Since then, Westergaard has received numerous death threats. Last year an axe-wielding Somali was sentenced to at least nine years in prison for breaking into Westergaard's home.