European Commission President Jose Manuel Barroso visits Russia on Thursday at a time of unusual prickliness in East-West relations.
By Stephen Mulvey
BBC News EU reporter
It's three weeks since US Vice-President Dick Cheney accused Moscow of using oil and gas as "tools of intimidation or blackmail" and two weeks since President Vladimir Putin described the US as a "Comrade Wolf" on the prowl.
The EU hopes to persuade Mr Putin to allow access to Russian pipelines
It is not much longer since the boss of Russian gas monopoly Gazprom warned that attempts to halt its expansion into Europe would "not produce good results", and would lead it to concentrate instead on China and North America.
European Commission spokesmen responded by saying this was precisely why the EU was trying to diversify its sources of gas and its supply routes.
The Russian press, which likened Mr Cheney's words to Winston Churchill's "iron curtain" speech, is using phrases such as "harsh confrontation" to describe relations with Europe.
The problem of energy security shot up the EU's agenda when a dispute between Russia and Ukraine disrupted supplies to member states at the beginning of the year.
The EU currently imports half of the gas it consumes, and half of the imported gas is Russian.
One response has been to intensify attempts to agree with Russia clear rules of the game, which will help regulate relations between Russia and transit countries, make it easier for Western firms to invest in Russian gas production, and introduce a degree of competition.
In the Black Sea resort of Sochi on Thursday, Mr Barroso and Austrian Chancellor Wolfgang Schuessel - the current president of the EU Council - will be urging Mr Putin to allow Western companies and Central Asian states to use Russian gas pipelines.
They will warn that, if this does not happen, Gazprom's attempts to get into the EU's gas retail market could fall foul of anti-monopoly regulations.
One immediate goal is to persuade Russia to ratify the Energy Charter treaty, which sets out clear rules for co-operation in the oil and gas business, and to agree the terms of an new protocol governing transit.
However, Commission spokeswoman Emma Udwin played down any likelihood of an outcome from this round of talks, saying it was a "moment for understanding each others' positions".
She said the two sides would be discussing the foundations for a renewed Partnership and Co-operation Agreement - signed in 1997 - and that a deeper energy partnership would be one aspect of this.
In the EU's view, she added, the partnership should be governed by the principles of "transparency, competition, and reciprocity".
One hawkish Russian view of the energy relationship was given by a presidential aide, Igor Shuvalov, in Tuesday's Nezavisimaya Gazeta.
"We are ready to supply Europe with oil and gas over the long term, but at the same time we will be taking on the role of leader...
"We will be expanding further, whether our European partners like it or not. We will do it together with European energy companies, if they want. But we will be in the lead, that is already clear."
Russian ambassador to the EU Vladimir Chizhov adopted a softer tone saying that just as Europe needed security of supply, Russia needed security of demand.
"The energy sector requires huge long-term investments, stretching not just years but decades and in order to be able to invest in the energy sector in Russia, both using domestic investment and attracting investment from abroad, Russian companies need to be sure that the product... will still have a market in 10 or 20 years time, it's only natural."
The summit will also focus on foreign relations - Iran and the Middle East - and on the countries in the neighbourhood of the EU and Russia, such as Belarus, on which the EU recently imposed sanctions.
On a brighter note, it is expected that agreements will be signed making it easier for some Russian visitors to get visas to visit the EU, and easier for both sides to send back illegal migrants.