Sanaa, Yemen (CNN) -- Two Yemeni Interior Ministry officials said two foreigners were kidnapped in the coastal province of Taiz, 250 kilometers south of the capital Sanaa, on Monday.
"The couple were walking down Hoban Street when they were kidnapped in open daylight by a number of armed gunmen," an Interior Ministry official said on condition of anonymity because he is not authorized to talk to the media.
No one has announced responsibility for the kidnapping. "They were forcibly put in a vehicle, which fled the scene immediately," the official added.
The second official said the victims were most likely South African nationals.
Witnesses said the couple were tourists and have been in the area for at least three days.
"They came to Taiz because foreigners are always welcomed here. This is the first time that foreigners are kidnapped in Taiz," said Khaled Al-Areeqi, a shop owner who saw the couple walking around. "The gunmen escaped the city unnoticed, and this is a result of bad security."
Numerous checkpoints were introduced throughout Taiz province, and the government has asked local tribal leaders to assist in the search. Armored vehicles were deployed at all entrances to the city.
Hundreds of security forces were deployed to surrounding rural areas.
Kidnapping of foreigners is common in Yemen and has increased since the political crisis that led to a regime change in February 2012. Monday's is the fourth kidnapping of foreigners this month.
Earlier in the month, five foreigners, including three staff members with the International Committee of the Red Cross, were released two days after being kidnapped by local tribesmen in the southern Abyan province.
A Finnish couple and an Austrian kidnapped in December were also released by suspected al Qaeda militants after receiving a ransom.