Russian President Vladimir Putin has defended the jailing of former oil tycoon Mikhail Khodorkovsky saying it was not politically motivated.

Mr. Putin spoke to reporters following a summit in St. Petersburg with European Union leaders that also covered the Kremlin's human rights record, trade and the Syria crisis.

Mr. Putin underscored a decision by the European Court of Human Rights that Khodorkovsky's conviction was not politically motivated.

Khodorkovsky was sentenced in 2005 for tax evasion, but critics say he was punished for having political ambitions.

When pressed by reporters about the opposition's demands to free some 40 people who they say are being held as political prisoners, Mr. Putin said he has no knowledge of anyone who could be described this way.

Mr. Putin also defended a controversial law that would impose heavy fines on protesters taking part in unsanctioned demonstrations and rallies, saying it is similar to legislation in other parts of Europe.

Mr. Putin returned to the presidency in May for a historic third term after facing some of the country's largest protests since the collapse of the Soviet Union. His critics say he rules the country through a tightly controlled political system and corruption — a charge he strongly denies.

He hosted the EU leaders for the first summit of his new presidency. They included European Council President Herman Van Rompuy, European Commission President Jose Manuel Barroso and EU foreign policy chief Catherine Ashton.

Russia is expected to join the World Trade Organization at the end of the year after 18 years of negotiations. As a member of the WTO, the Kremlin will be required to abide by global trade rules.

Mr. Barroso says European leaders are looking forward to working with Russia.

The leaders also discussed the Syria crisis and Russia's defense of the government of President Bashar al-Assad in the face of a violent opposition backlash. The talks failed to resolve differences on how to deal with Syria's 15-month-long conflict.