Two Saudi nationals were injured in the bombings in Boston but neither is accused of involvement even though one was initially put under armed guard at a hospital, the Saudi embassy said on Tuesday.
The embassy in Washington said that two of its nationals, one man and one woman, were wounded in Monday's blasts. Police earlier said that the 20-year-old man was being guarded but was not under detention.
US authorities told the embassy late on Monday that "no Saudi national was a suspect in the Boston Marathon attack and that the Saudi national in question was a witness, not a suspect", mission spokesman Nail Al-Jubeir said.
US investigators are still piecing together clues from Monday's attack and have not determined whether the assailants were from the United States or overseas.
The presence of a Saudi man drew initial, albeit cautious, attention from US media due to recent history. Fifteen of the 19 hijackers behind the September 11, 2001 attacks came from Saudi Arabia, a longtime US ally.
The attacks came as Saudi Arabia's foreign minister, Saud al-Faisal, visited Washington, where he met on Tuesday with secretary of state John Kerry.
Prince Saud offered "our solidarity with the great people of Boston in this tragedy" and said Saudi Arabia condemned every "terrorist act".
"We have felt the evil of the act of terror. We support the families and we give our condolences to the families of Boston," he told reporters in English after the talks.
Prince Saud said that Boston was "considered one of the homes" for Saudis due to the large number who studied in the city's numerous universities. He said that the injured Saudi woman was married to a student.
"We hope she is well and we hope well to all those who have been injured," he said.