Moscow: Moscow will not give out passports to Russians mobilised by the army, a government information portal said Wednesday, as fears of travel restrictions rise and tens of thousands flee the country.

"If a citizen is summoned for army service or received a summons (for mobilisation), he will be refused a passport," the government website said.

It added that those who are not issued a passport will be notified how long the hold will be in place.

Since President Vladimir Putin announced a mobilisation to prop up the Russian army in Ukraine, tens of thousands have crossed into neighbouring countries to evade the draft.

Many have feared that men of military age would be barred from leaving the country, with reports that some have already been turned away.

Only a minority of Russians hold a passport that allows them to leave the country.

Russia also has a system of "internal passports" -- a document used as a form of ID and accepted in some of Russia's ex-Soviet neighbours.

The portal did not mention restrictions on the handout of those documents.

Russians can travel to Armenia, Belarus, Kazakhstan and Kyrgyzstan -- where many have fled to since Putin announced mobilisation -- on internal passports.