How do I say 'call the police'?

Chinese emergency numbers use a different system from the Western 911-all-in-one. Each service has its own number, and knowing them matters:

• 110 — Police (pronounced yāo yāo líng, not yī yī líng. 1 is often read as yāo in phone numbers and room numbers to avoid confusion with 7)
• 120 — Ambulance / medical emergency
• 119 — Fire

报警 is the verb for contacting police — it covers calling them, walking into a station, and filing a report. For an emergency in progress, 快报警！(Call the police now!) is the urgent form.

For reporting an incident at a police station: 我要报案 (I want to report a case) is the formal phrase. For lost property: 我东西丢了 (I lost my things). For theft: 我被偷了 (I was robbed / something was stolen from me). The police will ask for your passport if you are a foreigner.

A practical note: many Chinese police stations have officers who can handle basic English, but bringing a Chinese-speaking friend or having key phrases written down helps significantly. The police report (报案回执) is a document you may need for insurance claims or embassy assistance.