ATHENS (Reuters) - Communication channels between the European Union and Turkey must remain open, Germany's foreign minister said on Thursday in an escalating row over campaigning by Turkish politicians in Europe.


Turkey has been embroiled in a dispute with Germany and the Netherlands over campaign appearances by Turkish officials seeking to drum up support for an April 16 referendum that could boost Turkish President Tayyip Erdogan's powers.


"Turkey certainly isn't on the verge of joining (the EU), but in no case should we close communication channels, even though things are difficult," Foreign Minister Sigmar Gabriel told reporters during an official visit to Athens.


Ankara has accused its European allies of using "Nazi


methods" by banning Turkish ministers from addressing rallies in Europe over security concerns. The comments have led to a sharp deterioration in ties with the European Union, which Turkey still aspires to join.

The row has placed Europe in a particularly awkward position with Ankara, which has seen its decades-old bid to join the bloc move at snail's pace due to concerns over its human rights record, ethnically-split Cyprus, and reluctance among some European countries to admit a largely Muslim nation.

Turkey is an integral part of a deal to keep hundreds of thousands of refugees and migrants fleeing the Middle East and beyond from moving to Europe, in return for 3 billion euros ($3.23 billion) in EU financial aid to Ankara.

More than one million people crossed from Turkey to Greece in 2015, but a deal to contain the numbers has now reduced the flow to a trickle.

"It is in Turkey's interests to stick to its promises," Gabriel said.

"The deal with Turkey includes financial assistance, and I assume it is in its interests to ensure the deal is kept."

(Reporting by Renee Maltezou, writing by Michele Kambas, editing by Ed Osmond)