YANGON, Myanmar (AP) — Police in Myanmar repeatedly used tear gas and rubber bullets against crowds protesting last month’s coup. But the demonstrators regrouped Tuesday after each volley and tried to defend themselves with barricades as standoffs between protesters and security forces intensified. Myanmar authorities have escalated their crackdown on the protests in recent days. The United Nations said it believed at least 18 people were killed on Sunday by security forces. Foreign ministers from Southeast Asian countries were meeting Tuesday to discuss the increasingly volatile crisis. Despite the crackdown, demonstrators have continued to flood the streets. The Feb. 1 coup reversed years of slow progress toward democracy in Myanmar after five decades of military rule.