The United Nations on Friday suspended all travel into areas held by Yemen’s Houthi rebels after more of their staff were detained by the rebels.

The United Nations said on Friday that the Houthis who control northern Yemen had detained an unspecified number of U.N. personnel, and it was suspending movement in all Houthi-held areas while seeking the detainees' immediate release.

In June, the Houthi's detained 11 employees from Yemen as the rebels kept cracking down on areas under their control.

The move will authorize harsher penalties on the Iran-backed group, which has attacked Israel and disrupted global shipping trade in the Red Sea for over a year.

The United Nations has announced that the Houthis, controlling northern Yemen, have detained several UN personnel. In response, the UN has suspended staff movement in Houthi areas while demanding their release.

The United Nations (UN) says it has suspended all movement in Houthi-held areas of Yemen after a number of UN personnel were detained by the armed group in the capital, Sanaa. The UN said that it was actively engaging with senior Houthi officials to try to secure the release of all its detained employees.

Yemen's Huthi rebels have detained another group of UN personnel, a United Nations statement said on Friday, after 13 staff were held last June.

The UN said on Friday it was suspending “all official movements” in Houthi-controlled parts of Yemen after the rebel group detained a number of people employed by the world body. The office of the resident UN co-ordinator for Yemen called for the “immediate and unconditional” release of all its detained staff held in the country.