Roads have been emptied and people were ordered to stay indoors in parts of Taiwan, including Taipei, for an air-raid exercise in case of a Chinese "attack."

Sirens for street evacuation drills were sounded at 1:30 PM when towns and cities were shut down across northern Taiwan for 30 minutes.

"It is necessary to make preparations in the event of a war," Taipei mayor Ko Wen-je said in a speech after supervising the Wan An drills - Wan An means 'everlasting peace.'

In Taipei, police ushered cars and other vehicles to move to the side of the road, whereas pedestrians were told to seek shelter. On the other hand, shops and restaurants pulled down their shutters, turning off lights to avoid getting targeted at night.

Since the beginning of the war in Ukraine, the island has raised its alert level. For the past two years, Taiwan has been meaning to carry out street evacuation drills, but they were constantly canceled due to Covid-19. The evacuation drill will be conducted next week.

Read next: China believes Taiwan using Ukrainian crisis for political manipulations

The United States has provided Taiwan with numerous weapon systems and supported pro-independence elements there.

Beijing's foreign ministry has reiterated on numerous occasions that the one-China principle was a political foundation of US-Sino relations, explaining that the US violated its own obligations and has been jeopardizing bilateral cooperation as well as peace and stability in the region.

China promises 'strong measures' if Pelosi visits Taiwan

The British Financial Times reported, on Saturday, that in case Nancy Pelosi, Speaker of the US House of Representatives, goes forward with the anticipated visit to Taiwan in August, China has openly warned of "strong measures".

Six sources with knowledge of the Chinese warnings said they were much more severe than previous threats Beijing has made when it disagrees with US actions or Taiwan policy.

However, according to one of these sources, China has previously indicated "stronger opposition" to the US in private. Other people, with knowledge of the circumstance, claimed that the private language went even farther by speculating on a potential military response.

Regarding whether the administration had asked Pelosi to postpone her trip, the National Security Council declined to comment. The Speaker made her own decisions, according to John Kirby, chief of strategic communications for the NSC, who stated on Friday that the NSC staff gave "context, facts, and geopolitical relevant information."

Previously on July 19, China had warned against the visit in April when Pelosi was supposed to embark on her tour, saying it would have a severe impact on Sino-US relations. However, the tour was postponed due to the House speaker testing positive for Covid-19 at the time.