Based on my research, I can verify this claim with multiple authoritative sources:

Reasoning:

• NATO launched Operation Allied Force on March 24, 1999, to halt the humanitarian crisis in Kosovo¹²³
• The operation lasted exactly 78 days, ending on June 10, 1999, when Serbia agreed to withdraw its forces from Kosovo³²¹
• The campaign included extensive bombing of Belgrade, the capital of Yugoslavia, with specific incidents including the bombing of the Chinese Embassy on May 7, 1999³⁴⁵
• On April 3, 1999, central Belgrade was hit by NATO missiles for the first time, targeting the FRY and Serbian Interior Ministries⁴
• The bombing targeted Serbian government buildings and infrastructure in an effort to destabilize the Milosevic regime³

The 78-day figure is consistently reported across NATO's official records, academic research institutions, and historical archives.

Overall validity: 100%

1. Operation Allied Force: Lessons for the Future - RAND
2. Kosovo Air Campaign (March-June 1999) | NATO Topic
3. NATO bombs Yugoslavia | March 24, 1999 - History.com
4. A Kosovo Chronology | War In Europe | FRONTLINE - PBS
5. Final Report to the Prosecutor by the Committee Established to ...