Maris Bergholds, a 23-year-old sociology university student on a hitch-hiking tour of the Middle East, said in a letter to his mother he was jailed by American soldiers when he sought help after being robbed.
Many soldiers had no idea what or where Latvia is and were suspicious of his foreign accent.
The Baltic country's foreign ministry said representatives of the tiny Latvian contingent in occupied Iraq would meet the student, but a spokesman added that he did not yet know where Bergholds was being held exactly.
Bergholds who set off in early June wrote to his mother Regina that his "nightmare" began after he got robbed.
"I turned to police and asked for their help to find my camera. The authorities detained me," he wrote in the letter dated 22 September.
"The most terrible thing was when they [US soldiers] banged my head on the doors of an army jeep ...[assuming that] I am a possible foreign fighter," he said in the letter, delivered by the Red Cross and received by his mother last Thursday.
"There are only foreigners in my prison... I have been in different prisons since 25 August," he wrote.
Foreign ministry action
The foreign ministry said it had asked the US embassy in the capital Riga and the Latvian armed forces to try and check the facts in the letter.
"The most terrible thing was when they [US soldiers] banged my head on the doors of an army jeep"
It said Latvian representatives in Iraq were planning to take Bergholds in, should he be released, until he can be sent back to Latvia.
Latvia has 111 soldiers serving in the stabilisation force in Iraq, where occupation forces blame many of the dozens of daily resistance attacks on its troops on "foreign fighters".
Bergholds's mother told journalists her son "has an artistic soul, he is so vulnerable."
"He is not a fighter," she said. "He went to Iraq as a student to collect an information for his thesis and he also wanted to write a book."
"Most of all I want Maris to know that we are informed about him and we try to rescue him," she added.