A senior U.S. official says a reported offer to upgrade Taiwan's fleet of F-16 fighters will provide the same level of quality as the more advanced fighters that Taiwan is seeking to purchase.

The official, who briefed reporters Monday on condition he not be identified, was seeking to refute charges by Taiwan and its supporters in the U.S. Congress that the Obama administration is caving in to China.

The official said he could not confirm the upgrade offer until it is formally reported to Congress on Wednesday. But he said an upgrade of Taiwan's 145 F-16 A/B jets would would provide Taiwan with more of the sophisticated warplanes at a lower price.

Taiwan has been asking since 2007 to purchase 66 F-16 C/Ds, made by Lockheed Martin Corporation. The C/Ds have better radar and more powerful weapons systems than the A/Bs, but the official said an upgrade would bring the existing planes to essentially the same level as the C/Ds.

Taiwan's deputy defense minister complained at a conference in the United States Monday that the upgrade offer shows Washington is yielding to Chinese pressure. Andre Yang said the U.S. government is becoming more wary of arms sales to Taiwan because China is reacting more strongly to them.

He also said Taiwan plans to continue to push to purchase even more sophisticated F-35s, saying the island will need them in the future.

The senior U.S. official denied that the administration is giving in to China, which warned in state-controlled media Monday that the arms sale will have “severe consequences.”

He said the scale of arms sales to Taiwan over the past two years is “unprecedented,” far outpacing that of the previous Bush administration.

Taiwan worries that it is falling behind in an arms race with China, which has been rapidly increasing its military spending for two decades. China considers Taiwan a renegade province that must eventually be reunited with the mainland, if necessary by force.