The German businessman was snatched in the centre of Sanaa

Police said the German - reported to be in his 50s - was abducted by tribesmen from the Bani Dhibyan tribe and taken to the Kholan region, about 100 kilometres (60 miles) east of Sanaa.

The German worked as director of the technical department for the Yemeni franchise of German carmaker Mercedes, the French news agency AFP reported, quoting a company official.

The attack came as the Yemeni President Ali Abdullah Saleh arrived in Germany on a state visit to discuss financial support for his country's economic reforms.

Spate of kidnappings

Two other Germans were kidnapped in separate incidents earlier this year. Both were released unharmed after several weeks in captivity.

Kidnappings of foreigners are common in Yemen.

Generally, tribesmen from disadvantaged areas take hostages and demand better services from the government or the release of jailed clansmen.

Almost all abductions have been resolved peacefully through mediation.

However, four Western tourists were killed in 1998 following a botched rescue attempt by government forces.

Angered by the kidnappings, which have harmed the tourist industry in Yemen, the government passed a law two years ago making abductions punishable by death.

Three convicted kidnappers have since been executed.