Earlier in the day, reports emerged in the media that hundreds of Saudi-sponsored protesters gathered in Kuwait city to protest against Iran.
An Iranian foreign ministry officially requested the Kuwaiti charge d'affairs to convey the Iranian protest to the Kuwait government, IRNA news agency reported.
The ministry stressed that such a gathering in Kuwait was a violation of international norms and undermined the good neighborly ties between the two countries.
Nimr demanded more rights for Shiites, who are a minority in Saudi Arabia.
The incident resulted in a row all across the Middle East over the issue, with Saudi Arabia severing diplomatic ties with Iran.