China issued a last-minute warning to US President Barack Obama to call off a planned meeting with the Dalai Lama.
The talks with the Tibetan spiritual leader were due to take place at the White House last night (Hong Kong time).
Foreign Ministry spokeswoman Hua Chunying said in a statement: "For the United States leader to meet the Dalai Lama is a gross interference in China's internal affairs and a serious violation of the norms of international relations."
Hua sidestepped a question during a daily news briefing about whether Beijing would try to have the meeting cancelled.
But she said: "If any country deliberately insists on harming China's interests, in the end it will also damage its own interests and will harm the bilateral relations between China and the relevant country.
"[If] the US president wishes to meet any person, it's his own affair, but he cannot meet the Dalai Lama."
The meeting was due to take place in the White House Map Room, which is of less significance than the Oval Office.
This was intended to highlight the Dalai Lama's capacity as a cultural and religious leader instead of a political one.
The two previously met in February 2010 and July 2011, both times in the Map Room.
National Security Council spokeswoman Caitlin Hayden said the US supported the Dalai Lama's approach, but recognised Tibet to be "a part of the People's Republic of China".
Hayden said: "We do not support Tibetan independence."
The planned meeting was scheduled to take place days after US State Secretary John Kerry's visit to Beijing.
Obama and President Xi Jinping are due to meet at a nuclear security summit in the Netherlands next month.
Analysts said both sides were carefully trying to contain the political damage of the meeting.
Jin Canrong , of Renmin University's School of International Relations, said the meeting reflected US efforts "to maximise its political benefit domestically and minimise its negative impact on Sino-US relations".
He said: "While using the encounter to show the Obama administration's concern over human rights in China, the White House is trying to avoid being trapped in controversy over the issue of China's sovereignty over Tibet."
The Dalai Lama gave a speech to the American Enterprise Institute, a conservative think tank, in Washington on Thursday.
He did not address the issue of Tibet, but stressed the general need for "compassion, tolerance and forgiveness" in the world.