China’s foreign ministry spokesman said Monday that Beijing “firmly opposes” the Obama administration’s plans to upgrade Taiwan’s aging fleet of F-16 fighter jets, but the measured tone suggested Chinese leaders may want to avoid sparking a full-scale confrontation with Washington over the issue.

When President Obama last year announced a deal to sell $6.4 billion in arms to Taiwan, including missiles, Black Hawk helicopters and mine-clearing ships, China reacted ferociously, canceling planned military contacts between Washington and Beijing and sending relations into a months-long deep freeze.

But ties have improved, following Chinese President Hu Jintao’s state visit to Washington in January, and Vice President Biden’s follow-up visit to China in August. Some analysts said China needed to register its displeasure over the latest deal, but did not want to risk another rupture in relations.

“China firmly opposes the U.S. arms selling to Taiwan,” foreign ministry spokesman Hong Lei said. He said China’s position remained “consistent and clear.”

Hong said China urged the United States to “refrain from selling arms to avoid impairing the Sino-U.S. relationship as well as the peaceful development of the relationship across the strait.”

Chinese leaders may also be calculating that the plan to refurbish Taiwan's old fleet of F-16 A/Bs marked a concession by Washington. Taiwan had been seeking to purchase more advanced F-16 C/Ds, a request the Obama administration has so far denied.