Why did Ukraine expel two Iranians over a missile purchase?
Kyiv's account of a failed Kh-31 purchase and a Russian parliamentary demand over Latvian schools featured in reports around 3 April 2018.

What had two Iranians tried to buy in Kyiv? On 3 April 2018, reports from the preceding days pointed to an answer: a Kh-31 missile. The government of Ukraine stated, on 30 March 2018, that it had expelled the two earlier in the year for attempting the purchase, which it said violated United Nations sanctions.
The same day, 3 April 2018, brought a separate development elsewhere in the region. Russian MPs called for sanctions against Latvia in response to plans to make Latvian mandatory for all students in the country's secondary schools. Latvia is a country where a quarter of the population is ethnic Russian.
The two items concerned different countries and different disputes. In Ukraine's case, the government framed the expulsions as enforcement of UN sanctions. In the Latvian case, the dispute centred on language of instruction in secondary schools and the response of Russian lawmakers.