The Yemeni coast guard seized a French or American boat in Hudaydah, Mohammed Ali al-Houthi said on his Twitter account.
What matters is that this boat is a foreign one, he added in his tweet, according to Arabic-language Rai al-Yaum.
The seizure came as French newspaper Le Figaro reported on Saturday that French special forces are present on the ground in Yemen.
On Friday, the French Defense Ministry said that France was studying the possibility of carrying out a mine-sweeping operation to provide access to the port of Hudaydah once the Saudi-led coalition had wrapped up its military operations.
France, along with the United States and Britain, backs the coalition in the Yemen conflict and provides weapons to both Saudi Arabia and the United Arab Emirates.
The Saudi-led coalition and its mercenaries began a massive operation on Wednesday to bring Yemen’s port city under their control.
While the Yemeni army and popular committees are fighting off the assailants and countering attacks on residential areas, international humanitarian organizations have warned of dire consequences of any escalation of violence around Hudaydah.
UN Humanitarian Coordinator Lise Grande has said “as many as 250,000 people may lose everything -even their lives,” if there is a military attack on Hudaydah.