US Defense Secretary Ashton Carter on Thursday called Iran's brief detention of American sailors in the Gulf earlier this year an "outrageous" action inconsistent with international law.

Iran held 10 US sailors for less than 24 hours in January after intercepting them in Iranian territorial waters off Farsi Island in the Persian Gulf when their two small attack boats mistakenly veered off course.

"Iran's actions were outrageous, unprofessional, and inconsistent with international law," Carter said today in remarks before the Senate Armed Services Committee.

"Nothing we've learned since then about the circumstances of this incident changes that fact."

The United States carefully avoided escalating the situation at the time, maintaining a conciliatory tone with Tehran days ahead of the implementation of a historic international deal over Iran's nuclear program.

Iranian media broadcast humiliating images of the American sailors during their detention, showing them kneeling on their boats at gunpoint with their hands on their heads.

The US military says a navigation error caused the American riverine command boats to veer off course.

The 59-foot (18 meter), lightly armed vessels were traveling from Kuwait to Bahrain.

Carter -- who reacted several days after the incident by saying he was "very, very angry" -- Thursday said the Iranian nuclear deal would not prevent the Defense Department from mobilizing to "deter Iran's aggression, counter its malign influence and uphold our ironclad commitments to our regional friends and allies, especially Israel, to whom we maintain an unwavering and unbreakable commitment."

On Tuesday, Iran said it had retrieved thousands of pages of information from devices used by the American sailors.