He said McGee's actions were in total contravention of Article 41 of the Vienna Convention on Diplomatic Relations.
The Vienna Convention reads: "Without prejudice to their privileges and immunities, it is the duty of the persons enjoying such privileges and immunities to respect the laws and regulations of the receiving state. They have a duty not to interfere in the internal affairs of that state."
Mumbengegwi said the summoning constituted the first warning to the U.S. ambassador that the government would not tolerate any interference in the country's internal affairs.
"The government of Zimbabwe will not hesitate to invoke the relevant provisions of the conventions and protocols which govern the conduct of diplomatic relations between states," he said.
Asked what course of action the government would take if McGee persists with his actions, Mumbengegwi said it would depend entirely on "what happens next."
He said other ambassadors who have also committed such acts would be duly warned.
"All diplomats and all ambassadors are fully aware of the provisions of these protocols and conventions. They will also be warned."
(Xinhua News Agency May 18, 2008)