Chinese police on Saturday offered rewards of $1,400 for information about 18 people it said were Taiwanese military psychological operations officers spreading "separatist" messages, a day after Taiwan pledged to boost its defenses.

China views democratically governed Taiwan as its own territory, over the strong objections of the government in Taipei, and has increased its military and political pressure against the island.

The public security bureau in the Chinese city of Xiamen, which sits opposite Taiwan on the other side of the Taiwan Strait, said the 18 were core members of the Taiwanese military's "psychological warfare unit" and published their pictures, names, and Taiwan identity card numbers.

The unit handles tasks such as disinformation, intelligence gathering, psychological warfare, and the broadcast of propaganda, the security bureau said in a statement.

"For a long time they plotted to incite separatist activities," the bureau said, adding there would be rewards of up to $1,400 for tips leading to their arrest.

They launched websites for smear campaigns, created seditious games to incite secession, produced fake video content to mislead people, operated illegal radios for "infiltration," and manipulated public opinion with resources from "external forces," the state-run Xinhua news agency said in a separate report.

Taiwan's defense ministry said the accusations reflected the "despotic and pig-headed thinking of an authoritarian regime ... trying to divide our people, belittle our government, and conduct cognitive warfare."

China has repeatedly issued such reports that "exploit the free flow of information in our democratic society to piece together and fabricate personal data," the ministry said.

"Defending national security and protecting the safety and well-being of the people is the unshirkable duty of every military officer and soldier," it said.

The wanted notice is largely symbolic, given that Taiwanese intelligence officers do not openly visit the country and China's legal system has no jurisdiction on the island.

On Friday, President Lai Ching-te pledged greater efforts to boost Taiwan's defenses, calling on China to renounce the use of force to seize the island. China reacted with anger, calling Lai a troublemaker and a "war-maker."

In June, China issued a similar bounty for the arrest of 20 people Beijing said were Taiwanese military hackers. Taiwan dismissed that threat, saying it would not be intimidated.