Jakarta – An American journalist will be deported from Indonesia after immigration officers said he entered the country illegally, despite granting him a visa when he arrived three weeks ago, the immigration department said.

William Nessen, who is from New York, was detained Sunday after visiting the tsunami-ravaged Aceh region. In 2003, the freelance journalist was imprisoned in Indonesia after he spent three weeks on the run with separatist rebels in the province.

Immigration spokesman Muhammad Indra said airport officials issued a visa to Nessen because they were not aware that a ban on his entry had been extended from August 2004 until August 2005. Indra said Nessen "would be ordered to leave Indonesia tonight," meaning Monday night.

Nessen told The Associated Press he was not aware that he had been barred from visiting the country. Nessen could not be reached for comment Monday. He was detained Sunday as he tried to leave Aceh and was taken to Jakarta on a plane chartered by immigration officials.

Nessen, whose wife is Acehnese, spent 40 days in jail in Aceh in 2003 for violating his visa by spending three weeks with separatist rebels from the Free Aceh Movement. During his time with the guerrillas, he contacted international media and accused the military of wanting to kill him.

Nessen has written articles on Aceh published in the San Francisco Chronicle and the Sydney Morning Herald.

The government banned foreigners from entering insurgency-torn Aceh for two years until the December 26 tsunami, when Jakarta was forced to open the province to international troops, aid workers and journalists.