The visa issue joins a list of difficulties between the EU and Russia that includes energy security, trade and human rights. The bloc is Russia’s biggest trading partner.

European diplomats say the visa dispute may be on the agenda when Dmitry Medvedev, who will be sworn in as president next month, attends the next EU-Russia summit in June.

One European diplomat said the numbers of people quitting Russia would increase if Moscow’s rules are not revisited, harming investment and damaging frayed relations even further.

Russia also has grievances about visas, accusing some EU countries of reneging on a deal to streamline procedures for issuing documents to Russian citizens and imposing surcharges.

In a joint letter, which Reuters has seen, EU embassies complained to officials that many Europeans find it impossible to collect all the paperwork necessary to live in Russia.

Work, student visa and residence rules “are very cumbersome and difficult to comply with … we observe an increased outflow of EU nationals out of the Russian Federation due to an uncertainty regarding their legal status,” the letter said.

The letter, sent on Monday, said many EU citizens were obliged to leave after a 90-day limit expires. It said a change in immigration procedures last year needed to be reviewed.

It was written by the European Commission and Slovenian Presidency on behalf of all 27 states and was sent to the Kremlin and senior government officials.

Russia has repeatedly said it wants to attract highly-skilled workers from abroad.

Last month Russian energy firm TNK-BP, half-owned by BP, told 148 foreign employees seconded to the firm that they must halt work as their visas did not comply with immigration rules.

The EU was warned by Russian officials in October that it faced “retaliatory measures” if countries like France, Belgium and the Netherlands did not respect a deal to streamline the issuing of travel visas.

The next EU-Russia summit in June is expected to kickstart talks on a wide-ranging partnership agreement. One long-term aim may be the abolition of all existing visa controls for travel and residence in Europe and Russia.

The European diplomat who participated in drafting the letter said some people had misused the Russian visa system by living in the country on the wrong type of permit.

But he added: “We are asking for goodwill and flexibility on the Russian side, so we don’t see an outflow of EU citizens from Russia which would lead to further bad relations.”

“It’s harming investment and company representative offices here who have hired expats,” he said. (Reuters)