By Oana Lungescu
BBC News, Prague
Mirek Topolanek will step down as Czech PM just hours after the summit
As the European Union welcomes six former Soviet republics to Prague, the summit is given added spice by instability in the region and the delicate question of relations with Russia.
The EU's "Eastern Partnership" initiative aims to forge closer ties with countries that Russia still sees as part of its sphere of influence - Armenia, Azerbaijan, Belarus, Georgia, Moldova and Ukraine.
It was proposed last year by Poland and Sweden, not only to boost the EU's fairly ineffectual "neighbourhood" policy, but also to act as a counterweight to the Mediterranean Union, launched with great fanfare by France last year to bring countries like Morocco and Egypt closer to the EU.
One word increasingly mentioned by diplomats when they talk about the EU's eastern neighbours is "instability". The war between Russia and Georgia last summer and the Russia-Ukraine energy row, which led to gas cuts to Europe in the depth of winter, have fuelled EU concern about events on the bloc's eastern borders.
More recently there was violent anti-government unrest in Moldova after a disputed election, and just this week an attempted army mutiny in Georgia.
The economic crisis, currently hurting the former Soviet Union as much as any other region in the world, only compounds those concerns.
To signal Germany's growing alarm, Chancellor Angela Merkel has decided to attend the summit in Prague.
Russia's military muscle in Georgia continues to alarm the EU
Last week, Germany and Poland called for the EU to co-ordinate financial assistance to Ukraine and send an EU mission there as soon as possible.
The German Foreign Minister, Frank-Walter Steinmeier, described Ukraine's economic situation as "worsening by the day".
The crisis, he said, was heightened by "the blockade at the top levels of the government" - a reference to the debilitating rivalry between Ukraine's President Viktor Yushchenko and Prime Minister Yulia Tymoshenko - which made reforms very difficult, as well as tensions with Russia.
Polish Prime Minister Donald Tusk is also coming, but the absentees include the leaders of France, Britain and Spain.
France will be represented by Prime Minister Francois Fillon and the UK by Foreign Secretary David Miliband.
"It's a bad signal," said an EU official. "We shouldn't give the impression that only Eastern European countries support this policy."
Czech political woes
To add to the embarrassment, the Czech government fell earlier this year, so Prime Minister Mirek Topolanek, who hosts the meeting, has to step down just hours after the summit.
And confusion over the guest list does not end there.
While there is little to stop Belarussian President Alexander Lukashenko from flying to Prague - after the EU suspended a travel ban last year as a reward for the release of political prisoners - few EU leaders would be prepared to shake the hand of a man often dubbed "Europe's last dictator".
Azerbaijan stands to gain from big energy deals with the EU
So the First Deputy Prime Minister of Belarus, Vladimir Semashko, will be despatched instead.
Moldova's Communist President Vladimir Voronin, whom the opposition accuses of rigging the recent election, will also stay away.
The Czechs pointedly addressed their invitations to the states of Belarus and Moldova.
The leaders of the other four ex-Soviet countries - who received personal invitations - confirmed they would attend.
The offer on the summit table is also disputed. The EU wants to show it cares, but is afraid of giving away too much. It has earmarked more than 600m euros (£530m; $800m) for the Eastern Partnership until 2013, but just over half (350m euros) is new money.
There is the prospect of more energy co-operation and better trade conditions, but not of eventual EU membership - disappointing for Ukraine and Moldova.
Germany and others also oppose any promise of getting rid of visa requirements in the next few years.
"All the six countries would like visa-free travel tomorrow," said an official, "but no one in the EU wants to talk about more than visa facilitation" for certain categories of people, such as students and researchers.
Yet Russia's Foreign Minister Sergei Lavrov has accused the EU of trying to carve out a new sphere of influence in what Moscow defines as its region of "privileged interest". Last week he said the EU had given him assurances that the initiative was not directed against Russia and he wanted "very much to believe" them.
The EU insists that the Eastern Partnership is not an anti-Russia alliance or a sphere of influence.
"We're responding to the demands of these countries," said one official, "and the economic reality is that most of their trade is done with the EU".
The political reality, though, is that most ex-Soviet republics seem divided between Moscow and Brussels and are playing one off against the other.