Nine foreign nationals, mostly women and children, have been kidnapped by Shia rebels in a mountainous area of northern Yemen, officials have said.
The group of seven Germans, including three children, a Briton and a Korean, had been on a picnic on Friday in Saada, Yemen's interior ministry said.
State-run media said the foreigners, among them two nurses, had been working at Jumhuri hospital in the region.
The Huithi Zaidi rebel group denied any part in the kidnapping, AFP reported.
A state-run Yemeni news agency cites an official source as saying the group also included two female German nurses, a German engineer and his wife, a British engineer and a Korean teacher.
However, there has been no confirmation of the kidnapping from their native countries.
Seoul would only say a South Korean woman was missing in Yemen.
"We have yet to confirm whether she has been kidnapped or not. We are requesting the Yemeni government to help locate her group there," an official told AFP.
The German foreign ministry said its embassy in Sanaa, the Yemeni capital, was in "close contact" with authorities.
A UK Foreign Office spokesman said it was investigating the reports of a kidnapping.
More than 200 foreign nationals have been kidnapped in Yemen in the last 15 years. Most have been released unharmed.
AFP reported a Yemeni official saying the kidnappers were members of the Huthi Zaidi rebel group which has been fighting the government for the last five years.
But a spokesman for the group dismissed the accusation as "baseless".
"It is a government conspiracy to tarnish the Huthis' reputation. It has never happened that a member of the Huthi followers committed such a shameful act," he said.
State media says this latest kidnapping comes just a day after 24 medics were released after being kidnapped by armed tribesmen in the Amran region.
The news agency quotes a source saying the Huthi Zaidis were responsible but AP news agency says they played no part.
Yemen's north-western province of Saada, up against the border with Saudi Arabia, has seen sporadic fighting between government troops and Zaidi rebels.
Zaidis belong to an offshoot of Shia Islam. They are a minority in mainly Sunni Muslim Yemen, but make up the majority in the north-west of the country.
Thousands of people have died since the Zaidis began a rebellion against government troops in Saada in 2004. They are accused of trying to seize power and impose religious law.