U.S. President Barack Obama (2nd R) shakes hands with Vietnam's Communist Party General Secretary Nguyen Phu Trong after they spoke to reporters following their meeting in the Oval Office at the White House in Washington July 7, 2015. REUTERS/Jonathan Ernst/File Photo

BEIJING (Reuters) - China is happy to see Vietnam normalizing relations with the United States and hopes it benefits regional peace, China said on Friday as the United States considers lifting a three-decade-old arms embargo on Vietnam.

A debate within the U.S. administration on lifting the arms embargo is coming to a head amid preparations for President Barack Obama to visit Vietnam this month. The former enemies are increasingly partners against China’s growing territorial assertiveness in the South China Sea.

Vietnam says it would welcome the United States “accelerating” the lifting of a lethal arms embargo, which would reflect trust between the two countries and recognition of its needs to defend itself. The ban was eased in late 2014.

“From the Chinese government’s point of view, we are happy to see Vietnam develop normal relations with the relevant country,” Chinese Foreign Ministry spokesman Lu Kang told a daily news briefing, when asked about the possible lifting.

“We also hope this relationship can benefit regional peace, stability and prosperity,” he added, without elaborating.

The arms embargo is one of the last major vestiges of the Vietnam War era. The United States has not indicated publicly it would remove the embargo and has long said such a move would depend on Vietnam showing progress on human rights.

Lifting the embargo would mark a major step forward in ties 21 years after normalization began.

U.S. engagement with Vietnam was stepped up rapidly during 2014, in what experts say was a calibrated move by the United States to seize on deteriorating ties between Vietnam and communist neighbor China over rival territorial claims in the South China Sea.

Vietnam has been boosting its military deterrent as China intensifies its fortification of South China Sea islands it controls or has built from scratch.