Translate the following English sentence to French:
"We feel the deepest regret and trust that, at long last, the authorities will succeed in cracking down on this terrorist organisation which has been a thorn in the side of Greece and its international relations for the past 25 years."
Notre peine est vraiment profonde et nous formons le vu que les autorités parviendront enfin à porter un coup à cette organisation terroriste qui, depuis 25 ans, met à mal le pays et ses relations internationales.