Eight more tourists have disappeared in Algeria, bringing to 29 the number of foreigners who have recently vanished while on vacation in the north African country.

The eight — all Austrians — were reported missing by their relatives on Friday, when they failed to board a ferry in the Tunisian capital Tunis as planned. The tourists relatives had not heard from the tourists, who were traveling in the Sahara Desert, for days.

Besides the Austrians, five groups of tourists — 16 Germans, four Swiss and a Dutch national — have disappeared in Algeria since the end of February.

Most were last seen traveling in a desert region of southeastern Algeria frequented by smugglers and drug traffickers. It includes the towns of Illizi and Tamanrasset.

Germany last week advised against traveling to the area, near the borders with Libya and Niger, because of the risk from criminal groups that operate there. Austria issued a similar warning, urging all Austrians in Algeria to immediately leave or to contact the Austrian embassy.

On Saturday Austria sent two diplomats and two officers from a special police unit to southern Algeria to search for the eight, Foreign Ministry official Franz Lang told the Austria Press Agency.

The four will work with officials from Germany and Switzerland who are already searching for tourists from those countries who are missing in the same region.

In Berlin, Germany's Foreign Ministry decided to send five German federal police agents to Algeria Sunday to help reinforce those already involved in the search.

Also Saturday, Austrian Foreign Minister Benita Ferrero-Waldner called her Algerian counterpart, Abdelaziz Belkhadem, and asked him to help find and safely return the tourists.

Belkhadem promised to help and to personally support an investigation looking into the disappearances, the Austrian Foreign Ministry said.

The missing Austrians, all from the Salzburg area, range in age from 25 to 69. They entered Algeria on March 17.

Islamic extremists waging an insurgency in Algeria for more than a decade have not carried out attacks in the vast desert region. Still, there has been speculation that insurgents may be behind the disappearances.

Tourists have been found dead in the desert in the past, stranded because they ran out of gas.