* Relations soured by energy, trade disputes
* EU concerned by Russian actions on civil, human rights
By Adrian Croft
BRUSSELS, Dec 21 (Reuters) - Russian President Vladimir Putin and European Union leaders are likely to clash over issues ranging from Syria to trade, energy and human rights on Friday when Putin holds his first talks in Brussels since his re-election as president in May.
Relations between the 27-nation bloc and Russia, its main external supplier of energy and a key trading partner, have been soured by rows over gas pipelines and brewing trade disputes over cars and pigs.
European leaders have taken issue with the jailing of members of punk band Pussy Riot, prosecutions of opposition figures and laws restricting protests and foreign-funded organisations since Putin was re-elected.
EU foreign policy chief Catherine Ashton said in September such moves constituted "a trend that is of very serious concern to the European Union".
Russian and EU officials expect no breakthroughs in Putin's talks with European Commission President Jose Manuel Barroso and European Council President Herman Van Rompuy. Some commentators are surprised Putin is bothering to make the trip.
"The last few EU-Russia summits have achieved very little and for Putin I think it is really a box-ticking exercise and I am almost surprised he is going at all," said James Nixey, an expert on Russia at London's Chatham House thinktank.
No meeting of minds is likely over Syria where Russia has been sharply at odds with Western powers over a conflict that has killed more than 40,000 people since an uprising against President Bashar al-Assad began in March 2011.
France and other Western states have criticised Russia for vetoing three U.N. Security Council resolutions aimed at pressuring Assad.
Energy, long a source of conflict between Brussels and Moscow, is set to dominate the Brussels talks.
Europe relies on Russia to cover around a quarter of its natural gas needs, but over the past decade Moscow has had a series of disputes with its ex-Soviet neighbours - Ukraine and Belarus - that disrupted its gas exports to Europe.
Those disputes increased the EU's determination to diversify supply away from Russia.
Ukraine's president pulled out of gas supply talks with Putin at the last minute on Tuesday, raising new concerns about the reliability of supplies to Europe.
The EU's executive Commission added to tensions between Europe and Moscow in September when it opened an investigation into suspected anti-competitive market practices by Russia's state-dominated Gazprom.
Another energy dispute expected to crop up at the summit is over Gazprom's Nord Stream gas pipeline.
Nord Stream carries gas from Russia to Germany, avoiding the eastern European transit states, such as Ukraine which Moscow has had pricing disputes with in the past.
Gazprom owns 51 percent of Nord Stream, putting it at odds with EU law preventing suppliers of energy from dominating distribution networks within the EU.
Russia maintains that the EU legal provision, which could force it to sell off part of its stake, is a restriction on trade that is contrary to World Trade Organisation rules.
The issue "is certainly one of the obstacles that has to be addressed by Russian and EU energy companies," Vladimir Chizhov, Russia's ambassador to the EU, said this week.
Trade disputes will also be high on the agenda in the talks, which will also involve Russian Foreign Minister Sergei Lavrov, Energy Minister Alexander Novak and Economy Minister Andrei Belousov.
EU Trade Commissioner Karel De Gucht said this month time was running out for Russia to settle trade disputes with the EU on everything from pigs to cars and he threatened to take Moscow to the WTO.
The EU says Russia, which joined the WTO this year after a 19-year wait, unfairly levies fees on imported vehicles, unreasonably bans EU exports of live animals and makes it costly for the bloc to export hundreds of products, especially wood.