Donetsk residents flee fighting; Russians report spike in Ukrainian refugees

Donetsk, Ukraine (CNN) -- Long lines of cars jammed the roads leading south out of Donetsk in eastern Ukraine Saturday, as residents attempted to flee the city center after a night of heavy shelling on the city's northern outskirts.

Hundreds of vehicles were caught in heavy traffic, and trains are no longer running in and out of the city, which is a stronghold for the pro-Russia rebels.

There was heavy shelling and antiaircraft fire on the outskirts of the city to the north throughout the night. There has been sustained fighting in the area for weeks, but it appeared more intense overnight than in recent days.

Russian news agency Interfax reported a dramatic increase Saturday in the number of Ukrainian refugees seeking refuge over the border in Russia.

Ukrainian civilians caught in crossfire More weapons for rebels in Ukraine

An additional 4,600 people have moved into temporary camps over the past 24 hours, Interfax cited Russian Emergency Situations Ministry spokesman Alexander Drobyshevsky as saying. This has pushed the total number of refugees staying in such camps above 31,000, he said.

Russia has opened 20 new temporary settlements for Ukrainian refugees in the past day, Drobyshevsky told Interfax, bringing the total number provided to 433. More than 11,000 children are among those staying there, he said.

CNN cannot independently confirm the report.

According to the latest figures from the United Nations' refugee agency, UNHCR, a total of 141,972 Ukrainians had fled to Russia this year because of unrest in eastern Ukraine, based on information from the Russian Federal Migration Service as of July 22. More than 41,000 of those Ukrainians are reported to have applied for asylum.

An additional 101,617 Ukrainians were reported as internally displaced within Ukraine as of July 22, the UNHCR said.

However, the refugee agency noted that because of the lack of a centralized registration system, the real number of those who have fled their homes is unknown and is likely to be higher.

'Various organizations report that some displaced persons from the East are reluctant to apply to the authorities because they fear retribution, want to maintain a low profile, and moreover, see little benefit in identifying themselves as there is no special reception procedures established for them,' the UNHCR said.

While most have fled conflict in the country's east, others have left Ukraine's southeastern Crimea region, which was annexed by Russia in March, and the areas around the capital, Kiev, and the cities of Odessa and Lviv in the west.

UNHCR spokeswoman Melissa Fleming told reporters in Geneva a month ago that most of those arriving in Russia had not requested asylum.

'Most people are seeking other forms of legal stay, often we are told because of concerns about complications or reprisals in case of return to Ukraine,' she said. Many are being accommodated in tented camps around the southern city of Rostov-on-Don, she said.

Groups of pro-Russian rebels have been fighting Ukrainian government forces in eastern Ukraine's Donetsk and Luhansk regions since April.

The sides continue to trade accusations over who was responsible for bringing down Malaysian Airlines Flight 17 on July 17, with the loss of all 298 passengers and crew aboard.

But the international outrage over the downing of MH17 has not stopped the conflict.

Ukrainian federal tanks were seen moving in to closer positions by the morning, a rebel commander told CNN. The tanks were within a kilometer or two of improvised rebel lines along the northern city perimeter.

One woman told CNN, 'I want you to tell the world the terrorists must stop bombing us, we are a peace-loving people.' As she said the word 'terrorists,' she pointed toward the Ukrainian army side.

The Ukrainian authorities, in turn, routinely refer to the pro-Russia rebels as terrorists.

According to the Twitter feed for the press office of the self-declared Donetsk People's Republic on Saturday, fighting has occurred at five border checkpoints that appear to be on the Russian side of the Ukraine-Russia border.

Russia's state-run RIA Novosti news agency also reported fighting at five border checkpoints, naming three places on the Russia side of the border, Novoshakhtinsk, Kuybishevo and Gukovo.

CNN's Ingrid Formanek reported from Donetsk and Laura Smith-Spark wrote and reported in London.