According to the Russian Interfax news agency, a piece of space junk has hit a coolant radiator on the U.S. portion of ISS.
The source says that no coolant has escaped from the system and that NASA engineers are analyzing images to assess the damage.
Readers should be aware that I have tried without success to find the NASA website the story claims is the source for this information. Moreover, this story is reported nowhere in the U.S. press, and it is strange for a NASA website to report something like this and it not be quickly picked up by the U.S. press.
Thus, I am not entirely convinced yet that this story is accurate.
Update: a commenter below has provided this link to a subsequent post at nasaspaceflight about the impact.