Russia's transportation ministry is banning Ukrainian airlines from flying to Russia, a measure taken in response to Ukraine's ban last week on Russian flights.

The mutual bans underline the fierce tension that remains between the countries over Russia's backing of separatist militias in eastern Ukraine. Although fighting between the separatists and Ukrainian forces has quietened in recent months, a firm resolution of the conflict appears to be distant.

More than 8,000 people have been killed since the fighting began in April 2014, according to UN estimates.

Ukraine's ban last week said the country would also close its airspace to Russian flights carrying military or dual-purpose material. But state news agencies' reports Monday on the Russian ban did not mention a similar stipulation.