Whereas in April the Americans said they wanted to arrest Mr Sadr for the murder last year of a fellow cleric, Mr Allawi has indicated that he would be happy if the Mahdi Army simply left Najaf.
The European Union brought in a long-contested warrant that allows police in one country to arrest people wanted in another for any of 32 crimes, many of them unrelated to terrorism.
Police said Mr. Smith had an extensive arrest history, for crimes including robbery, assault and promoting prison contraband, and had been wanted since April 25 for absconding from parole.