The presidents of Ukraine and Poland have pledged to overcome bitter historical disputes and strengthen their strategic partnership, which both see as a key alliance in eastern Europe against a belligerent Russia.
Warsaw is a staunch supporter of Kiev in its grinding war with Russian-led separatists and in opposing Moscow’s 2014 annexation of Crimea, but disagreement over second World War-era events continues to undermine their relations.
Poland regards as genocide the murder of some 100,000 Poles by Ukrainian independence fighters in the 1940s, and is angered by the glorification of wartime nationalist leaders such as Stepan Bandera in Ukraine today.
Ukraine accepts that wartime militia committed atrocities against Poles but denies they amounted to genocide, and it wants Poland to officially recognise and protect places on its territory where Ukrainians were killed and buried.
Kiev stopped allowing Polish historians to conduct exhumations in western Ukraine this year, and in response Poland banned Ukrainian officials with alleged nationalist and “anti-Polish” views from entering the country.
Cemeteries and monuments in both countries have been vandalised and on Saturday an anti-tank grenade was fired at an empty Polish tourist bus in western Ukraine. In March a Polish consulate in the region was hit with a similar weapon.
"We reached a common view that history should not influence the strategic character of Ukrainian-Polish relations," Ukrainian president Petro Poroshenko said on Wednesday.
“Both I and [Polish president Andrzej Duda] have an absolutely clear understanding that only one side benefits from historical conflicts between Ukraine and Poland. It’s not Ukraine or Poland, but Russia.”
Laying flowers
After laying flowers with Mr Duda at a memorial in eastern Ukraine to victims of the Soviet secret police, Mr Poroshenko said they had agreed to raise the status of an inter-governmental commission on historical questions, which should soon allow exhumation work to resume in western Ukraine and eastern Poland.
“It is a very important element,” Mr Duda said. “I made a very clear appeal to [Mr Poroshenko] today to restore agreement for exhumations on both sides of the border, so that each memorialisation can be based on the results of research,” he said.
“In the context of history, we should ensure at all costs that we strive for truth and do not allow lies to cast a shadow on relations between our countries and, above all, between our peoples.”
Mr Duda also said that Poland supported Kiev's desire for a United Nations peacekeeping mission with a strong mandate to be sent to eastern Ukraine, where fighting since spring 2014 has killed more than 10,000 people and displaced 1.6 million.
The presidents also discussed boosting energy co-operation, their shared opposition to the planned Nord Stream 2 gas pipeline between Russia and Germany, and establishing joint customs controls on their border to cut corruption.