Taiwan renewed its call Aug. 17 on the U.S. to sell it advanced weaponry as it joined Japan in vowing to keep a close eye on China's rising military power.
Taipei and Tokyo were reacting to the release of a U.S. Defense Department report which warned that China's expanding capabilities are changing the strategic balance in East Asia.
"We hope the U.S. can continue to supply Taiwan with defensive weapons in accordance with the Taiwan Relations Act, including F16 C/Ds, diesel submarines and other items we have requested," Taiwan defense ministry spokesman Yu Sy-tue said.
Taiwan has repeatedly stated its wish to acquire the F16 C/Ds - an upgraded version of the F16 fleet currently deployed by the island - and the diesel submarines, but the U.S. government has so far been non-committal.
Earlier this year, Beijing reacted angrily to an arms deal between Washington and Taiwan, saying it would cut military and security contacts with the U.S.
"China has not given up the use of force against Taiwan and we are closely monitoring China's military developments. We ask the public to rest assured," Yu said.
Using similar wording, Japan said it would "keep paying attention to China's military trend."
"It will have a significant impact on security in the region, including Japan, and on the international community," a defense ministry spokeswoman in Tokyo said.
"China is activating its navy in the East China Sea and in the Pacific," the spokeswoman said.
She said the defense ministry thought Beijing was extending its activities far offshore with the aim of protecting its territory, pre-empting Taiwan's possible independence and safeguarding its economic sea lanes.
China considers Taiwan, where the mainland's defeated nationalists fled in 1949, to be territory awaiting reunification, by force if necessary.
In April, Tokyo protested after a Chinese naval helicopter made a close fly-by of one of its destroyers on the high seas off a southern Japanese island chain during exercises Japan considered provocative.
A similar incident took place near the Okinawan islands in the same month when 10 Chinese naval vessels, including two submarines, were seen sailing through international waters between Japan's southernmost islands.
In its annual report to Congress, the U.S. Defense Department said Monday that China was ramping up investment in an array of areas including nuclear weapons, long-range missiles, submarines, aircraft carriers and cyber warfare.
The Pentagon paper estimated that China's overall military-related spending was more than $150 billion in 2009, including areas that do not figure in the publicly released budget.