In international relations, threats or pressure between countries can be carried out in many covert ways. Here are some common methods: 1. **Economic sanctions**: Imposing economic pressure by restricting a country's trade, investment or financial activities to force it to change its policies or behaviors. 2. **Cyber attacks**: Using network technology to attack other countries' infrastructure, government websites or financial systems to cause chaos, loss or panic. 3. **Information warfare**: Influencing public opinion or interfering with the political process of other countries by manipulating or spreading false information, rumors or propaganda. 4. **Espionage**: Obtaining confidential information of the other country through intelligence gathering, infiltration and espionage to enhance one's own strategic advantage. 5. **Diplomatic isolation**: Using diplomatic means to alienate other countries from the target country, thereby isolating the target country in the international community. 6. **Military deterrence**: Gathering troops or conducting military exercises in neighboring areas to show threatening intentions and force the other party to consider compromise. 7. **Proxy war**: Indirectly exerting pressure and influencing the target country by supporting hostile forces or non-state actors in the other country. 8. **Financial manipulation**: Influencing the currency value and economic stability of the target country by manipulating the international financial market. 9. **Cultural penetration**: Subtly influencing the values and ideology of the other country through cultural exchanges, educational cooperation, etc. These means are usually not easy to detect, but can have a profound impact on state relations if they persist. When using these strategies, countries need to carefully evaluate the possible consequences and countermeasures.