MADRID (Reuters) - The Spanish police said on Thursday it had arrested the former head of Venezuela's military intelligence unit, Hugo Carvajal, who had been in hiding since a Spanish court approved his extradition to the United States almost two years ago.

       "Arrested tonight in Madrid "Pollo Carvajal", fugitive from justice and wanted for extradition to the US," the Spanish police said in a tweet, which a included a video of the detention.

       The police did not give any further details of his arrest and just said that Carvajal was "living totally isolated."

       Carvajal's lawyer in Spain, Maria Dolores Arguelles, confirmed that Carvajal had been arrested but declined to give further details besides saying that her client would appear before Spain's High Court on Friday morning.

       Carvajal was a former general and ally of late Venezuelan leader Hugo Chavez.

       U.S. officials have long sought Carvajal because they believe, if he is willing to cooperate, that he could provide a treasure trove of information on the alleged drug activities of Venezuelan President Nicolas Maduro and his associates.

       (Reporting by Jesús Aguado; editing by Emma Pinedo and Sandra Maler)