Cross-strait tensions have been on the rise since 2000, when independence-leaning politician Chen Shui-bian became Taiwanese president.

They have been fueled lately by Chen's plans to revise the island's constitution, which have been characterized by some analysts in mainland China as a backhanded attempt to introduce a timeline for achieving Taiwan's independence.

According to the Pentagon survey, Chinese political leaders as well as commanders of the People's Liberation Army do not remain idle in the face of these challenges.

"The PLA's offensive capabilities improve each year and provide Beijing with an increasing number of credible options to intimidate and actually attack Taiwan," the department said in its annual report on China's military might sent to Congress at the end of the week.

Beijing's arsenal arrayed against Taiwan includes approximately 500 short-range ballistic missiles deployed in Nanjing military district.

If equipped with adequate guidance systems, these missiles could destroy key Taiwanese leadership facilities, military bases and communication and transportation nodes with minimal advanced warning, Pentagon analysts point out.

Some of these weapons are believed to be capable of hitting US military bases in Okinawa, Japan.

Taiwan still maintains a qualitative edge over the mainland in air power, boasting three times as many modern so-called "fourth-generation" fighter jets as China.

But Beijing is working hard to close the gap.

China's air force now has nearly 3,400 aircraft, and its share of fourth-generation planes, mainly Su-27 and Su-30 fighter-bombers purchased from Russia, is increasing steadily, the report pointed out.

"Over the next several years, given current trends, China most likely will be able to cause significant damage to all of Taiwan's airfields and quickly degrade Taiwan's ground-based air defenses and associated command and control," the document warned.

Ground forces targeting Taiwan include three army groups deployed in Nanjing district that include a plethora of special operations units.

But the Pentagon believes China would have trouble mounting a D-Day-style invasion of the island "throughout the remainder of the decade" primarily because of its lack of a credible amphibious lift capability.

Chinese military planners believe the United States will likely come to Taiwan's rescue in case of its showdown with the mainland, which continues to view Taiwan as a renegade island, according to the report.

To counter US aid, the Chinese military are likely to use naval mines, submarine and cruise missile to attack a US aircraft carrier.

It may even resort to high-altitude nuclear blasts in the hope that its electromagnetic effects would interrupt communications and jam radars, the Pentagon warned.

The report contains sharp criticism of the Taiwanese army, which it says "has major shortcomings in training and reservist mobilization."

Taiwan's naval operations "are not well integrated with those of the army and air force, and multi-mission training is infrequent," it said.

The report is like to spark calls for larger US military assistance to Taiwan in Congress, which counts many Taiwan advocates among Republicans.

A pro-Taiwan amendment has already been introduced in a 422.2 billion-dollar defense authorization bill that passed the House of Representatives earlier this month.

The amendment, sponsored by Representative Jim Ryun, calls for senior military officer exchanges with Taiwan that will focus on anti-submarine warfare, missile defense and other defense matters.

WAR.WIRE