Complex sentence: In one incident, 10,000 Cubans stormed the Peruvian Embassy requesting asylum, and so the U.S. agreed that it would accept 3,500 refugees, with Castro conceding that those who wanted to leave could do so from Mariel port.
Split into simpler sentences: In one incident, 10,000 Cubans stormed the Peruvian Embassy requesting asylum, and so the U.S. agreed that it would accept 3,500 refugees. Castro conceded that those who wanted to leave could do so from Mariel port.