The deployment began before US President Donald Trump's meeting with his Chinese counterpart Xi Jinping in Beijing and increased to more than 100 after the summit ended, a security official told AFP on the condition of anonymity.
Trump has caused jitters in Taipei after suggesting US arms sales to Taiwan could be used as a bargaining chip with China, which claims the island is part of its territory and has threatened to seize it by force.
Taiwan relies heavily on US support to deter any potential Chinese attack.
In a post on X, Taiwan National Security Council chief Joseph Wu shared a map dated May 23 showing "China's Maritime Deployment", with Chinese navy and coast guard ships dotted from the Yellow Sea off the Korean Peninsula down to the South China Sea and in the Western Pacific.
"In this part of the world, #China is the one & only PROBLEM wrecking the #StatusQuo & threatening regional peace & stability," Wu said in the post.
Marine survey and research ships are also among the more than 100 vessels, the security official told AFP.
It is not clear what the vessels are doing, but Chinese navy and coast guard vessels have previously trained in these waters.
China has ramped up military pressure on Taiwan in recent years, deploying fighter jets and warships around the island on an almost daily basis and staging several large-scale drills.
- Arms sales -
Several thousand people, some waving US and Taiwan flags, marched in Taipei on Saturday in support of the government's plan to boost defence spending.
Under US pressure, President Lai Ching-te's government had proposed additional spending of nearly $40 billion on critical weapons, including US arms and domestically-made drones.
But the plan was blocked by the opposition-controlled parliament, which passed $25 billion in spending on US weapons only.
Taiwan's government has been on the offensive since Trump's remarks on arms sales, insisting US policy has not changed and that arms sales are part of Washington's security commitment to the island.
A Chinese foreign ministry spokesman told a news conference on Friday that Beijing's "position of resolute opposition to US arms sales to China's Taiwan region is consistent, clear and firm."
Trump on Wednesday referred to "the Taiwan problem" when asked if he would speak to Lai about arms sales to the island.
"I'll speak to him. I speak to everybody," Trump said, adding that he had a great meeting with Xi during his state visit.
"We'll work on that, the Taiwan problem," Trump said.
Lai said Thursday he would be "happy" to talk to Trump.
Such a conversation between the presidents of Taiwan and the United States would break more than four decades of diplomatic protocol and risk angering China.
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