* Greece, others need to change border attitude - president
* No need to close internal borders, external controls vital
* Minsk deal condition for good relations with Russia
By Tim Hepher
RIGA, Nov 29 (Reuters) - The president of Latvia has urged Greece to demonstrate a "changed attitude" on border security to stem a flow of migrants, but sees no need to re-erect Europe's internal frontiers in response to the refugee crisis or Paris attacks.
President Raimonds Vejonis told Reuters he also backed European support to help Turkey deal with over 2 million refugees from Syria, while expressing concern about Russia's growing involvement in Syria's civil war.
Hundreds of thousands of migrants fleeing conflict have poured into Europe from the Middle East and Africa this year, straining external borders along Europe's southern flank.
"This is the reason why we really need a changed attitude of Greece and others on border security. They need stronger control and checks of documents on their border because they are the first country that asylum seekers are reaching," Vejonis said.
Amid deep divisions over Europe's worst refugee crisis since World War Two, officials from Baltic states have voiced similar concerns about Italy, whose islands have also faced an influx.
Hundreds of Latvians protested in August against a government decision to accept 250 asylum seekers over two years as part of a European Union plan to deal with the migrants.
Vejonis dismissed calls for the Schengen agreement, a free border zone of 26 nations including 22 from the EU, to be frozen in light of the refugee crisis or the Nov. 13 attacks in Paris, conducted partly by militants who travelled freely from Belgium.
"I don't believe that we need to close borders because in reality these people who are involved in terrorism are already mainly European citizens. It means our security institutions need to work more carefully and intensively to recognise such individuals and detain them if necessary," he said.
German Chancellor Angela Merkel has said the open border system would only endure if EU member states accepted a permanent, mandatory quota system for sharing out refugees.
But Vejonis said the EU must first shore up its external frontiers, especially in the south, establish effective ways of returning non-war refugees and combat human trafficking.
"If the EU does not solve all these key issues, it will be very difficult in the future to discuss new decisions on reallocation and resettlement. It will be a very hot topic for us and if there are no solutions on these three points, it will be very difficult to continue."
The EU is due to hold a summit with Turkey on Sunday to discuss aid for the 2.3 million Syrian refugees there, but differences remain over what Ankara should provide in return.
"From a European point of view we need to organise good border control, but at the same time find the mechanisms for helping Turkey manage the 2 million or more people who have already arrived from Syria," Vejonis said.
Latvia is also examining what it can contribute to an anti-Islamic State coalition proposed by France, after sending a senior officer to the U.S. command centre for the Middle East.
But Vejonis, a former defence minister who is also commander of Latvia's forces, said Riga's priority would be to preserve its own security amid what Western officials have described as Cold War levels of military activity in the Baltic.
"The first task of our armed forces is to develop new capabilities here because relations militarily between the Baltic states, and between NATO and Russia, are still very challenging and we feel day-to-day the impact of Russian military activities along our borders on land, sea and air."
With ties between Moscow and Western capitals thawing after the Paris attacks, some of Russia's neighbours fear Europe's commitment to sanctions against Moscow over the Ukraine crisis may be waning as they co-operate in fighting Islamic State.
Vejonis said the EU's priority in dealing with Russia must remain full implementation of a deal to end fighting in east Ukraine, under the terms of the so-called Minsk agreement, which set a deadline of the end of 2015 for Ukraine to regain full control over its eastern border.
"No implementation, no good relations with Russia. My opinion is we need to continue negotiations to see how we can maintain sanctions against Russia, but I hope that all parties will really implement the Minsk Agreement," he said. (Additional reporting by Gederts Gelzis; Editing by Alison Williams)
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