Definition: In this task, a passage will be given and the goal is to identify an event from the passage. An event is defined as a single word representing something that happened, is happening, or may happen. An event can be factual or hypothetical, positive or negative, certain or uncertain. While most events are based on verbs, an event can also be based on a noun (ex. storm, snow, rainfall) or a copula verb (is, was, been, etc.). The event must not be a pronoun or an adjective. For noun events with multiple words, use the last word in the phrase as event.
Input: Passage: Kosovo has been run by a United Nations mission since 1999, when a NATO bombing campaign ended a crackdown by Belgrade on separatist ethnic Albanian rebels in the province. The UN envoy to Kosovo, Martti Ahtisaari, began negotiations in February with Serbian and Kosovo authorities to define the future status of the province.

began