A polio outbreak in Tajikistan has led the World Health Organization to send a team to investigate and offer support, the agency said Friday.

Since the WHO groups the Central Asian country in its European region, the agency calls it the "first importation of poliovirus in the WHO European Region since it was certified polio-free in 2002."

To date, poliovirus Type 1 has been isolated from specimens of seven cases out of 120 suspected cases in patients with acute flaccid paralysis, WHO said.

The majority of cases are children under five years of age.

All of the cases are in southwest Tajikistan, which borders Uzbekistan and Afghanistan, one of four countries where polio remains endemic.

No cases have been reported in the areas of Afghanistan bordering Tajikistan, WHO said.

WHO is communicating with countries in the region about the outbreak. Tajik and neighbouring health authorities may enhance surveillance and immunization.

No travel restrictions are currently recommended, but WHO said it's important for international travellers to and from polio-affected areas to be immunized.

For every child paralyzed by polio, several hundred others who are infected show no symptoms but can pass on the disease.

With files from The Associated Press