The Obama administration formally notified the US Congress on Wednesday of a potential $5.3 billion upgrade of Taiwan’s existing fleet of US-built F-16 fighter jets, a move that China is certain to oppose.

“Mainland China’s military expansion and threat against the ROC still exist,” Taiwan’s defense ministry said in a statement. ROC is short for the Republic of China, Taiwan’s formal name.

“Improving our defense capability is a crucial and only measure to sustain regional security and stable development across the (Taiwan) strait.”

China has shown no sign of ending an arms build-up that is focused on Taiwan, and past US arms sales to Taipei have riled Beijing, which has never renounced the use of force to bring the island under its control.

Taiwan, which for years relied on better equipment and training, has been hobbled by the refusal of any country aside from the United States to sell it weapons, fearing an angry response from China.

The military advantage Taiwan once boasted in the air has slipped away over the past decade as China modernized, and analysts say the arms deal would do little to alter the balance.

In January 2010, China froze military-to-military ties and threatened sanctions against US firms after President Barack Obama approved a potential $6.4 billion arms sale to Taiwan left over from the administration of George W. Bush.

In a commentary released earlier on Wednesday ahead of the announcement, China’s official Xinhua news agency warned that the US “should fully realize the hazard and sensibility of its arms sales deal with Taiwan and stop it to avoid any harm to China-US ties as well as cross-straits relations.”

Still, relations between China and Taiwan have warmed considerably since Ma Ying-jeou was elected the island’s president in 2008. Ma has since signed a series of landmark economic and trade deals with Beijing that have delivered a boom to Taiwan’s economy.

“The US sold defensive weapons to Taiwan in 2008 and 2010 and these arms sales did not change the direction of peaceful development across the strait,” the ministry said.

It reiterated that Taiwan will not seek an arms race with China, and added that the arms sales will make “people in Taiwan more confident to interact with mainland China.”

Taiwan will continue to seek the more advanced F-16 C/D fighters as well as diesel-electric submarines.