"diplomatic representatives" is correct and usable in written English.
This phrase is used in written and conversational English to refer to people who are authorized by a government to represent that government in a foreign land. For example, "The United States sent two diplomatic representatives to negotiate a trade agreement with China."
The extraterritoriality of ambassadors and other diplomatic representatives is likewise of long standing.
Diplomatic representatives from China, Ukraine, Nepal and Russia were also present.
The United States has diplomatic representatives in Taiwan but has formal diplomatic relations only with China.
Several countries sent diplomatic representatives to the airport to safeguard Mr. Guaidó's arrival.
It concluded by calling on all Libyan diplomatic representatives around the world "to stand with their people and condemn the crimes that are being committed against their people".
The General Conference of Weights and Measures (CGPM), with diplomatic representatives of some 40 countries, meets every six years to consider reform.
After the treaty was signed, Max von Brandt became diplomatic representative in Japan – first representing Prussia, and after 1866 representing the North German Confederation, and by 1871 representing the newly established German Empire.
Britain's Foreign Office announced that the Syrian chargé d'affaires, Khaled al-Ayoubi, the top Syrian diplomatic representative in Britain, had resigned because "he is no longer willing to represent a regime that has committed such violent and oppressive acts".
In 1999, just after the Kosovo war, Stewart became Britain's sole diplomatic representative in Montenegro.
With the Bolshevik seizure of power in Russia (October 1917), Litvinov was appointed diplomatic representative in London.
Senior Special Operations commanders pledged that their efforts would be coordinated with the senior diplomatic representative in each country.
