A view of a damaged medical clinic is seen at the explosion site in Tehran, Iran, June 30, 2020. At least 19 people were killed in an explosion at a clinic in the northern district of Iran's capital Tehran on Tuesday, said Jalal Maleki, spokesman for the Firefighting Organization of Tehran. (Photo by Ahmad Halabisaz/Xinhua)

Policemen and firefighters work at the explosion site in Tehran, Iran, June 30, 2020. At least 19 people were killed in an explosion at a clinic in the northern district of Iran's capital Tehran on Tuesday, said Jalal Maleki, spokesman for the Firefighting Organization of Tehran. (Photo by Ahmad Halabisaz/Xinhua)

Relatives of the victims react at the explosion site in Tehran, Iran, June 30, 2020. At least 19 people were killed in an explosion at a clinic in the northern district of Iran's capital Tehran on Tuesday, said Jalal Maleki, spokesman for the Firefighting Organization of Tehran. (Photo by Ahmad Halabisaz/Xinhua)

A man leaves the explosion site in Tehran, Iran, June 30, 2020. At least 19 people were killed in an explosion at a clinic in the northern district of Iran's capital Tehran on Tuesday, said Jalal Maleki, spokesman for the Firefighting Organization of Tehran. (Photo by Ahmad Halabisaz/Xinhua)

A damaged car is seen at the explosion site in Tehran, Iran, June 30, 2020. At least 19 people were killed in an explosion at a clinic in the northern district of Iran's capital Tehran on Tuesday, said Jalal Maleki, spokesman for the Firefighting Organization of Tehran. (Photo by Ahmad Halabisaz/Xinhua)

A firefighter works at the explosion site in Tehran, Iran, June 30, 2020. At least 19 people were killed in an explosion at a clinic in the northern district of Iran's capital Tehran on Tuesday, said Jalal Maleki, spokesman for the Firefighting Organization of Tehran. (Photo by Ahmad Halabisaz/Xinhua)

An Iranian policeman speaks to people at the explosion site in Tehran, Iran, June 30, 2020. At least 19 people were killed in an explosion at a clinic in the northern district of Iran's capital Tehran on Tuesday, said Jalal Maleki, spokesman for the Firefighting Organization of Tehran. (Photo by Ahmad Halabisaz/Xinhua)

Debris are seen at the explosion site in Tehran, Iran, June 30, 2020. At least 19 people were killed in an explosion at a clinic in the northern district of Iran's capital Tehran on Tuesday, said Jalal Maleki, spokesman for the Firefighting Organization of Tehran. (Photo by Ahmad Halabisaz/Xinhua)