WASHINGTON (Reuters) - The United States on Wednesday said it was tightening sanctions on some exports to Russia in response to the poisoning of Kremlin critic leader Alexei Navalny, partially excluding certain items such as those related to aviation and space. The U.S. Commerce Department, in a statement, said the move would tighten sanctions originally put in place in response to the March 2018 poisoning of former Russian military officer intelligence Sergei Skripal and his daughter in Salisbury, England, with a military-grade nerve agent. Moscow has denied any role in either case. The department “is committed to preventing Russia from accessing sensitive U.S. technologies that might be diverted to its malign chemical weapons activities,” it said. (This story corrects headline and first paragraph to say sanctions are being tightened after Navalny poisoning; corrects 2nd paragraph to clarify sanctions first put in place over Skripal poisoning)