The assessment concluded that there was no credible evidence that any adversaries had developed a weapon capable of causing the injuries that U.S. officials have reported.
The director, William J. Burns, has made periodic visits to Ukraine to meet with intelligence officials and to exchange information to the country’s president.
The hasty and sometimes inaccurate reaction from some countries to the fatal explosion in Poland was worrisome, but so is Russia’s nuclear temptation in Ukraine.