China confirmed Thursday it was assessing a report that at least two of its air force jets carried out an unsafe intercept of a US military spy plane over the contested South China Sea.
The Pentagon said on Wednesday that the Chinese J-11 tactical aircraft on Tuesday intercepted a US military spy plane.
"We have noted the relevant report," the Defence Ministry in Beijing told dpa in a statement.
"According to the report, this is very possibly related to a close surveillance of China by US military aircraft. We will assess the understanding of the relevant circumstances."
The incident comes amid heightened tensions in the region as China has sought to assert its control in the face of competing territorial claims from countries in the region.
The Chinese jets came as close as about 15 metres from the US aircraft, according to an unidentified defence official quoted in US news reports.
US State Department spokesman John Kirby said Thursday in Washington that such Chinese manoeuvres "are not doing anything to lessen tensions or to decrease the possibility for miscalculations."
"This is something that we routinely have raised in the past when it's happened," he said.
The US Defence Department is reviewing the intercept of what it said was a maritime patrol reconnaissance aircraft by two Chinese tactical aircraft, a Pentagon statement emailed to dpa said.
"The incident occurred in international airspace during a routine US patrol in the South China Sea," the statement said. "Initial reports characterized the incident as unsafe."
The Defence Department was addressing the issue through diplomatic and military channels.
China maintains territorial claims to most of the South China Sea, which includes overlapping claims with Vietnam, Taiwan, the Philippines, Malaysia and Brunei.
The US has not taken sides over the competing claims, but says the issue should be resolved diplomatically and asserts the US right to freedom of the seas.