The European Union and the United States have imposed further economic sanctions against Russia for its role in the conflict in Ukraine.

The EU sanctions will target Russia's oil industry, defence, dual-use goods and sensitive technologies.

The sanctions are to be reviewed after three months.

EU President Herman Van Rompuy said the broad sanctions are intended to be "a strong warning".

However, he said they could be reversed if Russia changes course in Ukraine.

German Chancellor Angela Merkel said the new economic sanctions were "inevitable".

She called on the Russian leadership to "pursue the path of de-escalation and cooperation" in the conflict, warning of further steps if it does not.

The new measures go beyond the asset freezes and visa bans used until now, instead imposing restrictions to increase the cost to Russia of its continued intervention and support of pro-Russian separatists in Ukraine.

US President Barack Obama has said the US has also imposed new sanctions on Russia in the areas of energy, arms and finance.

He said this evening that the US has blocked exports of goods and technology to the Russian energy sector.

Mr Obama said it had suspended export credit to Russia and financing for economic development.

He said the existing sanctions have made a weak Russian economy even weaker.

Mr Obama warned that Europe was losing patience with Russian President Vladimir Putin, but he denied it was the start of a new Cold War.

The US Treasury has announced punitive sanctions on three leading Russian banks, including the giant VTB.

The sanctions banned any Americans or people in US jurisdictions from any new medium or long-term financing transactions with VTB Bank, its subsidiary Bank of Moscow and Russian Agricultural Bank.

All three are controlled by the Russian government.

Russia has accused Ukrainian forces of firing across the border from eastern Ukraine into Russian territory using assault rifles and grenade launchers.

In a statement the Russian foreign ministry said: "We officially demand Kiev stop firing at the sovereign territory of the Russian Federation."

The Ukrainian government has denied firing into Russian territory.

Meanwhile, 17 people, including three children, were killed in the past 24 hours by shelling in Ukraine's rebel-held stronghold of Gorlivka, local Ukrainian officials said.

They said 43 people were also wounded in the city, which was observing three days of mourning for 13 civilians, including two children, killed on Sunday by Grad rockets.

Several homes were hit by artillery fire in the town located 45km north of Donetsk, the officials said.

The top storey of a school was destroyed and several units in a local hospital were also damaged, they said.

The United Nations has criticised the use of heavy weapons by both pro-Russian rebels and Ukrainian forces in inhabited areas, and in a report released yesterday said more than 1,100 had been killed by fighting since mid-April.

Russian Foreign Minister Sergei Lavrov and his US counterpart John Kerry have agreed in a phone conversation that fighting near the MH17 crash site needs to be stopped, Russia's Foreign Ministry said.

Dutch Prime Minister Mark Rutte also called Ukrainian President Petro Poroshenko to ask Ukrainian forces to stop fighting around the crash site, a government spokesman said. 

"The prime minister this morning called the Ukrainian president with a request to halt hostilities around the crash site," Jean Fransman said.

Fighting between Ukrainian troops and pro-Russia separatists has prevented international investigators reaching the site for a third day.

Tonight, it emerged that Mr Poroshenko has asked Belarus to host talks between Russian and Ukrainian envoys to discuss access to the crash site.

The talks in the Belarus capital would address "access by international experts to the site of the crash of Malaysia Airlines," the Ukrainian presidency said in a statement.

The Ukrainian military confirmed early this morning that violence was still raging.

"Pockets of insurgents are continuing to fire on Ukrainian positions from the towns of Snizhne, Torez and Shakhtarsk," it said, referring to towns within about 30km of the site.

The fresh conflict came a day after rebels admitted the Ukrainian government had regained control over part of the vast site, where the remains of some of the 298 victims from the MH17 crash still lie 12 days after the disaster.

Ukraine would not confirm the rebels' claim, saying only that its troops had entered a string of towns around the scene.

A Dutch and Australian police mission needs access to the site to recover victim remains and personal effects.

More than 200 bodies have already been recovered and sent to the Netherlands for identification.

The Netherlands and Australia were home to most of the people on the flight, which the West alleges was brought down by separatists.

Earlier, the head of the Dutch recovery mission vowed no remains of the crash victims would be left behind.

Pieter-Jaap Aalbersberg voiced frustration that international investigators had been blocked from reaching the site of the crash.

"It is frustrating to have to wait to do the job they came to do.

"Their motivation comes from the deep conviction that the relatives in all the different countries are entitled to have their loved ones and their personal effects returned to them," he said at a news conference in Kiev.

"If the experts find remains, they will be recovered immediately. We will be using a refrigerator train wagon near Torez.

"If the train is inaccessible for whatever reason, we will arrange other transport. We will not leave any remains behind."

Task force to deal with aircraft threats

World aviation chiefs have set up a "senior level" international task force to deal with the threat to passenger planes from ground-based weaponry.

A high-level safety conference involving more than 190 nations is to take place under the auspices of the International Civil Aviation Organisation (ICAO).

Following a meeting of global aviation bodies at ICAO's Montreal headquarters today, ICAO's secretary general Raymond Benjamin said all the aviation bodies "strongly condemned the use of weapons against the civilian aircraft".

He described the downing of MH17, with the loss of 298 lives, as "unacceptable" and he sent the aviation world's "deepest condolences" to the families of the victims.

Stressing that aviation was still a safe form of travel, Mr Benjamin said that the MH17 disaster had "raised troubling concerns" in respect of civilian aircraft.

He said the task force would be composed of state and aviation industry experts who would see how intelligence regarding the safety of planes could be effectively gathered and passed on to all those affected.

The safety conference he announced would take place in February 2015.