The arrest of an American academic in Thailand on charges of criticizing the monarchy has alarmed U.S. officials, the State Department said on Tuesday. The case represents a rare detention of a foreign citizen under Thailand’s strict lèse-majesté laws.

The academic, Paul Chambers, a lecturer in civil-military relations in Southeast Asia at Naresuan University in northern Thailand, was arrested on lèse-majesté charges and charges under the Computer Crimes Act, according to Tammy Bruce, a spokeswoman for the State Department. She said that the department was communicating with Thai authorities over his detention.

The lèse-majesté laws in Thailand are among the strictest in the world, and forbid defaming, insulting or threatening the king and other members of the royal family. Human rights groups have criticized the laws for suppressing free speech. Charges under the laws carry a minimum sentence of three years and a maximum of 15 years.

While Thai courts are expected to rule this year on hundreds of lèse-majesté cases, it is rare for a foreigner to be arrested under the laws.

“This case reinforces our longstanding concerns about the use of lèse-majesté laws in Thailand,” Ms. Bruce said in a statement. “We continue to urge Thai authorities to respect freedom of expression and to ensure that laws are not used to stifle permitted expression.”

Consular officers from the U.S. Embassy in Bangkok have requested access to Mr. Chambers, she said. “As a treaty ally of Thailand, we will closely monitor this issue and advocate for the fair treatment of Paul Chambers,” she said.