By Phuong Nguyen and Khanh Vu HANOI (Reuters) -Vietnam hailed a long-awaited trade deal with the United States as a breakthrough on Thursday and said negotiators were working to finalise details, as business groups awaited clarity on the finer points to assess the impact of the new tariffs.

Vietnam finds itself caught between its two biggest trading partners as the Trump administration tries to stop Chinese exporters using Vietnam as a way station.