A Chinese ship embroiled in a standoff with Vietnamese vessels last year has returned to waters near Vietnam as the United States accused China of pushing its presence in the South China Sea while other claimants are pre-occupied with the coronavirus.

Vietnamese vessels last year spent months shadowing the Chinese Haiyang Dizhi 8 survey vessel in resource-rich waters that are a potential global flashpoint as the United States challenges China's sweeping maritime claims.

On Tuesday, the ship, which is used for offshore seismic surveys, appeared again 158 km (98 miles) off Vietnam's coast, within its exclusive economic zone (EEZ), flanked by at least one China Coast Guard vessel, according to data from Marine Traffic, a website that tracks shipping.