A total of 127 people have died in Ukraine's east and south as a result of violence over the past weeks, a United Nations official reported Wednesday.

"More arms, and more arms" are being used in the standoff, as Assistant Secretary-General for Human Rights Ivan Simonovic was quoted by the Washington Post as telling the UN Security Council. 

Simonovic was referring to the conflict between rebels holding control of public buildings across Donetsk and Luhansk regions and Kiev's special forces carrying out a so-called "anti-terrorist" operation against them.

In his words, about 1000 people have registered as displaced people in the regions, but said he believed the real number could be much higher.

The UN's refugee agency (UNCHR) earlier reported its estimates suggesting that 10 000 people, "mostly ethnic Tatars, but also Ukrainians, Russians and mixed families", have fled the Crimean peninsula, recently absorbed by Russia, as well as Eastern Ukraine, opting for other parts of the country.

Adrian Edwards, UNCHR spokesperson, has said at least one-third of them are children.

Some of the displaced have been forced to move twice, first from Crimea and them from the unrest-torn eastern and southern regions.

UNCHR representatives have said they were committed to assisting those affected by the Ukraine crisis.

During his briefing to the Security Council on Wednesday, Ivan Simonovic also commented on the developments in the Black Sea city of Odessa, which took 48 lives in the first days of May following clashes between pro-Russian supporters and backers of independent Ukraine and also a fire at a trade union building.

Although he stopped short of throwing the blame for the death toll on either side having taken part in the incident, he pointed that UN's probe had shown six of the victims had died from gunshot wounds and all of them were pro-Ukrainians.

Speaking of the causes of the fire, he said it was "beyond doubt" Molotov cocktails had been "thrown by both sides, flying from the building and into the building".

He described the current situation in Ukraine as "not a favourable" one for presidential elections, which are to be held on May 25, but stressed the UN could only observe "violations related to the polls".