MOSCOW, Aug 25 (Reuters) - The Kremlin said on Tuesday it saw no need for now to investigate the circumstances of opposition politician Alexei Navalny's illness and that a German clinic's initial diagnosis of poisoning was not yet conclusive.

German Chancellor Angela Merkel on Monday called on Russia to investigate the suspected poisoning of Navalny and to hold the perpetrators accountable after German doctors found indications of a toxic substance in his body.

Kremlin spokesman Dmitry Peskov told reporters on a conference call the German clinic had not conclusively identified the substance behind Navalny's illness. He added it was unclear why the German doctors were "rushing" to use the word poisoning.

But he said that if poisoning was definitely established as a reason, then an investigation would be launched. (Reporting Tom Balmforth and Gleb Stolyarov; editing by Sujata Rao)