Nine foreigners, including seven Germans, were kidnapped in Yemen's northern Saada province, and officials on Sunday said a Shia rebel group was responsible.
The Yemeni Interior Ministry said those kidnapped included a German doctor, his wife and their three children, as well as a Briton and his South Korean wife and two other German nationals.
They were reportedly kidnapped while on a picnic in Saada.
The Foreign Ministry in Berlin confirmed that seven Germans are missing in Yemen. The state news agency said the foreigners worked in a hospital in Saada.
However, the rebel group accused of carrying out the kidnapping denied any involvement.
"This is a new conspiracy by the ruling regime to launch a new war and tarnish the image of the sons of Saada," the group said in a statement.
The Yemeni Interior Ministry said Sunday that it has organized a crisis team to deal with the kidnapping, and the German Embassy in Yemen said it has been in contact with local authorities.
It is not uncommon for tribesmen to abduct visitors to the country — bordered by Saudi Arabia and Oman on the southern tip of the Arabian peninsula — to gain concessions from the government.
In most cases, hostages are freed unharmed.