Opposition politician Alexei Navalny has been detained outside his home ahead of a rally in central Russia.

Officials in the city of Nizhny Novgorod last week refused to authorize Navalny’s rally planned for Sept. 29, saying another event had been planned at the same location on the same day.

Local police and prosecutors warned that “provocations” would be quashed if people chose to attend.

In an early Friday Instagram post, Navalny shared footage of two police officers approaching him in what appears to be an underground parking lot. They then ask him to “provide an explanation.”

“Oh, how old man Putin doesn’t want me to make it to the demonstration,” Navalny wrote.