Poland has temporarily shut down its consulates in Ukraine after a grenade attack damaged one of them in the border town of Lutsk early on March 29.
Both Ukrainian President Petro Poroshenko and Polish President Andrzej Duda condemned the attack, in which no one was injured.
The Ukrainian security forces issued a statement saying the incident was one of a series of "provocations against the Republic of Poland" that "are of benefit only to one party -- the Russian Federation."
A Poroshenko spokesman claimed on social media that Russian provocateurs had tried to orchestrate a prank phone call with Poroshenko by claiming to be Duda.
In an earlier phone call between the two presidents, Poroshenko invited Poland to participate in the investigation of the Lutsk attack.
Relations between Poland and Ukraine have been tested in recent months by several incidents of vandalism of World War II monuments that officials from both countries have also blamed on Russia.
Despite their historic enmities, Poland has been a staunch supporter of Ukraine's closer relations with the European Union and a leading advocate of sanctions against Russia for its 2014 annexation of the Ukrainian region of Crimea.
Editors' Picks
Top Trending
1
Russia Moving Military Assets To Africa After Syria Setback
2'So Much Death': Ukrainian Drone Pilot Shares Emotional Account Of Frontline Combat
3Ukraine Hits Kazan Buildings In Latest Display Of Drone Power
4What Would The Russian Capture Of Pokrovsk Mean For The Ukraine War?
5Mystery Photos Shed Light On Romania's 1989 Revolution
6Orban Says Higher NATO Defense Targets Would Cripple The Hungarian Economy
7Russia's Runaway Food Prices
8Russia Launches Massive Drone Attack As Putin Vows Revenge For Kyiv's Attack On Kazan
9Kyiv Hits Kursk After Massive Wave Of Deadly Russian Strikes On Ukraine
10Ukraine Live Briefing: Putin Has No Plans To Meet Trump, Kremlin Says
RFE/RL has been declared an "undesirable organization" by the Russian government.
If you are in Russia or the Russia-controlled parts of Ukraine and hold a Russian passport or are a stateless person residing permanently in Russia or the Russia-controlled parts of Ukraine, please note that you could face fines or imprisonment for sharing, liking, commenting on, or saving our content, or for contacting us.
To find out more, click here.