European Commission President Jose Manuel Barroso (pictured R above) said on Saturday that the European Union was thinking about tougher sanctions against Russia, after NATO estimated this week that at least 1,000 Russian troops were in eastern Ukraine supporting an anti-government insurgency there.

But he said the bloc also wanted a political deal to end the conflict.

"We are ready to take very strong and clear measures, but we are keeping our doors open to a political solution," Barroso said at a news conference in Brussels with Ukrainian President Petro Poroshenko.

Barroso stressed that the EU wanted to avoid confrontation with Moscow, saying that possible tighter sanctions would be intended only to push Moscow to negotiate.

"A new Cold War" would be "detrimental to all of Europe," Barroso said.

Poroshenko (pictured L above), for his part, condemned the Russian intervention in his country, saying there were now thousands of foreign troops and hundreds of foreign tanks in Ukraine.

He said he expected EU leaders meeting at a summit on Saturday to make a formal request to the EU's executive commission to draw up new sanctions measures that could be implemented if necessary.

'Deep concern'

EU foreign policy chief Catherine Ashton, speaking after an informal two-day meeting of EU foreign ministers in Milan, also called for a political solution.

"All ministers expressed deep concern about the recent aggression by regular Russian forces," Ashton said.

"They were very clear that there is no military solution. We need a sustainable political solution that respects Ukraine's territorial integrity and sovereignty," she added.

She said a decision on further sanctions against Russia would be made at Saturday's summit.

The EU and the US have already slapped the toughest sanctions since the Cold War on Moscow over the crisis.

Downed fighter

Ukraine's four-month conflict continued on Saturday, with Ukrainian forces saying one of their fighter jets was shot down by a Russian missile.

A Facebook statement said the pilot of the Su-25 ejected and was uninjured.

Pro-Russian separatists fighting the Kyiv government this week took control of the town of Novoazovsk with the apparent intention of pushing further west along the coast connecting Russia to the Crimean Peninsula, annexed by Moscow in March in a move that provoked outrage in the international community.

After appearing to lose momentum over the past few weeks, the separatists have also retaken a number of key towns in eastern Ukraine - which Kyiv alleges was made possible by direct Russian intervention.

Russia, however, continues to deny allegations by Kyiv and the West that it is supporting the separatists with military supplies and fighters.

Nuclear fears

Meanwhile, nuclear energy experts in Germany have expressed concern about the risk of nuclear power plants being caught up in the eastern Ukraine conflict. The largest nuclear power facility in Europe is situated at Zaporizhia, about 200 kilometers (125 miles) away from where fighting is underway.

In remarks published Saturday, Greenpeace nuclear expert Tobias Münchmeyer told the Essen-based newspaper the "Westdeutsche Allgemeine Zeitung" he was concerned the station's six reactors were not well-protected enough to withstand a direct bombardment. At 1.20 meters (4 feet) thick, the concrete shells surrounding them were strong enough to withstand only the crash of a small aircraft, he said.

"In the region there are many armor-piercing weapons which could penetrate these protective covers," Münchmeyer said, adding that the reactors were also of Russian design, largely dependent on Russian expertise and spare parts.

Top positions to be decided

Saturday's EU summit, though overshadowed by the conflict in Ukraine, is also to decide on Ashton's successor for the next five years. Italy's top diplomat, Federica Mogherini, is widely seen as front-runner for the job, despite some criticism that she lacks experience.

The summit is also to pick a new European Council president to replace Herman Van Rompuy. Polish Prime Minister Donald Tusk appears to be a favorite for the post, a choice that, if confirmed, would likely disconcert Moscow.

tj/nm (dpa, Reuters, AP)