The U.K.’s Special Boat Service (SBS) soldiers have been wounded in direct gunfights with Yemeni forces as part of a secret U.K. military campaign in Yemen, reported the Mail Sunday.

The U.K.’s Special Boat Service (SBS) troops have been injured in clashes with members of the Houthi Ansarullah movement, fighting against the Saudi-led coalition since March 2015.

The injured soldiers were repatriated back to the U.K. to recover, the report said.

"The guys are fighting in the inhospitable desert and mountainous terrain against highly committed and well-equipped Houthi rebels. The SBS’s role is mainly training and mentoring but on occasions, they have found themselves in firefights and some British troops have been shot," an SBS source said.

"In a contact a few weeks ago, an SBS guy was shot in the hand and another guy was shot in the leg. Their injuries were a reminder that this is a very dangerous assignment. Obviously, nothing about the mission will be confirmed publicly by the Ministry of Defense unless a U.K. soldier is killed – they’d have to announce that," continued the source.

The SBS mentoring teams inside Yemen include medics, translators and Forward Air Controllers (FACs), whose job is to request air support from the Saudis.

Andrew Mitchell, a British Member of Parliament and former Secretary of State for International Development, said the U.K. was “shamefully complicit” in Saudi Arabia’s war in Yemen and urged the government to explain the role of British troops in the conflict to the Parliament.

Officially, the U.K.'s government supports the peace process and a "sustainable political solution to the Yemen conflict."

Since 2015, the Saudi-led coalition has since received logistical and intelligence support from the U.S., U.K., and France.

The coalition has repeatedly been accused of violations of civilian rights. According to a new report from the University Network for Human Rights (UNHR) and Yemeni monitoring group Mwatana, U.S. and U.K. made weapons have killed and maimed nearly 1,000 civilians in Yemen, including children and women, since the start of the war in 2015.

Yemen's civil war has triggered one of the world's largest humanitarian crises. According to the UN Refugee Agency (UNHCR), 22.2 million are Yemenis now in need of humanitarian assistance. Those forced to flee their homes are especially at risk. 2 million people now languish in desperate conditions, away from home and deprived of basic needs.