The National Organization for Rights and Freedoms (Hood) has said that the Syrian intelligence services arrested a Yemeni businessman while he was leaving Damascus on Tuesday.
It added that the Syrian intelligence arrested Amer Ghalib Saeed, his wife and children.
It further said Saeed and his family was accompanied by a representative of the Yemeni Embassy to Damascus Airport, but after the representative left, Saeed and his family were arrested.
Hood quoted some relatives of Saeed as saying that they were mistreated, pointing that his wife and children were forced to return to their home and Saeed was held and taken into an unknown place.
Hood demanded the Yemeni government to immediately move to release Saeed and facilitate the return of Yemenis residing in Syria.
An officer of the Yemeni Embassy in Damascus was killed by armed men.
The Syrian authorities arrested tow Yemenis for three months without any charges.
Yemeni protesters repeatedly demanded the authorities to expel the Syrian Ambassador to Yemen after the escalation of violence against the Syrian people by the regime.
They condemned "massacres" committed by the Syrian regime against the Syrian people, demanding the Yemeni government to immediately expel the Syrian Ambassador.
Meanwhile, The Syrian Free Army has accused the Yemeni Shiite Houthi Group of sending its members to fight them in support of the Syrian regime.
The spokesman of the Syrian National Coalition, Wael Hafiz, said the Houthi Group was among other foreign groups which have sent their fighters to kill the Syrian people.
He urged through media the Houthi and Hezbollah fighters to leave Syria.