Ukraine's Greek Catholic Church head has said the country is facing a "humanitarian catastrophe" that is the most difficult human calamity in Eastern Europe since the Second World War.

"The aggression against Ukraine is a challenge for preserving peace in the world which cannot pretend that nothing happens in Eastern Europe," said Archbishop Sviatoslav Shevchuk, major archbishop of the Ukrainian Greek Catholic Church, Catholic News Agency reported June 7.

The Ukrainian Greek Catholic Church an eastern rite Catholic Church in full communion with the church in Rome.

The United States and German leaders said June 7 that sanctions on Russia must stay until it implements a deal to end fighting in Ukraine.

President Barack Obama and Chancellor Angela Merkel held talks as the G7 summit of economic powers began in southern Germany, the BBC reported.

In Geneva, the U.N. Office for the Coordination of Humanitarian Affairs said June 9 that Ukraine between mid-April 2014 and June , the crisis in Ukraine has internally displaced more than 1.3 million people.

The International Organization for Migration said June 9 that acccording to official data, more than 2 million Ukrainians have been displaced by the war in the East of the country.

These are mainly in the eastern provinces of Donetsk, Luhansk and Kharkivska, according to the Ukraine Ministry of Social Policy.

"During the same period, at least 6,454 people, both military and civilians, have been killed and 16,146 wounded, according to estimates from the UN Human Rights Mission in Ukraine and the WHO," said OCHA spokesperson Jens Laerke.

An estimated 878,000 Ukrainians had sought asylum, residence permits or other forms of legal stay in neighbouring countries as of 4 June.

"Insecurity continues in the east of the country. Heavy fighting on 3 June in Mariinka near Donetsk city caused casualties and displacement which further exposed people to the risk of unexploded ordinance and landmines as they fled outside of the main roads," said Laerke.

5 MILLION NEED AID IN UKRAINE

Overall, some 5 million people in Ukraine are in need of humanitarian aid and 3.2 million are being targeted for assistance in the UN-coordinated Humanitarian Response Plan.

Archbishop Shevchuk called on participants of this G7 Summit (of leaders from leading Western industrial nations) in Bavaria to work toward effective solutions.

The conflict erupted in Ukraine last year in February when the country's former pro-Russian president was ousted following months of violent protest, and a new government was appointed.

In March, Russia annexed Ukraine's eastern peninsula of the Crimea and pro-Russian separatist rebels have since taken control of eastern portions of Ukraine, around Donetsk and Luhansk.

The rebels in Ukraine have been supported by both Russian arms and troops, according to both Ukraine and Western nations and reports received by the office of the United Nations High Commissioner for Human Rights.

A ceasefire brokered in Minsk on Feb. 15 has not stemmed the fighting.

Archbishop Shevchuk told CNA May 28 that the conflict in Ukraine is not simply an isolated dispute, but rather has "serious global consequences."

He spoke of the Vatican's diplomatic commitment to helping find a peaceful solution to the Ukrainian conflict, as well as a possible visit of Pope Francis to Ukraine.

The archbishop told Vatican Radio on May 30 that despite the "so-called Minsk ceasefire agreement" each day there are reports of soldiers and civilians killed.

"So many people are in danger. The number of those who are forced to leave their homes is increasing. Right now there are almost two million displaced persons who had to flee from their homes.

"In that territory of Donbass, which is under occupation of the Russian troops, each day receive news of incoming of heavy weapons.

He noted that in the past few months "more than seven hundred tanks entered tanks entered" Eastern Ukraine from Russia and he asked why that was so.

"If we agreed to ceasefire, if we agreed to start a political process, if we are in favour of saving human beings in that territory, why somebody is investing in war?

"We have a fact of the most difficult humanitarian catastrophe after the end of the Second World War in the Eastern Europe. Why we would not invest in saving human lives?"