BEIJING - China firmly opposes foreign leaders meeting with the Dalai Lama "in any form", said Hong Lei, China's foreign ministry spokesman, in response to reports that he may attend an annual religious event in the US on Thursday which President Barack Obama is scheduled to attend.

"Tibet-related issues concern China's core interests and our national sentiment," Hong said on Monday. "We firmly oppose any country using Tibet-related issues to interfere in China's domestic affairs. We resolutely oppose any country's leaders meeting the Dalai Lama in any form".

Hong expressed his hope that the US would keep to their commitment in Tibet-related issues and handle the matter in the interest of bilateral relations.

The US National Prayer Breakfast, founded in 1953, is held annually in Washington, D.C. on the first Thursday of February. Every US president since Dwight D. Eisenhower has participated in the event. Obama is also scheduled to address the meeting.

Obama held a closed-door meeting last February with the Dalai Lama in the White House's Map Room, instead of the Oval Office where he usually meets with foreign leaders. The US President has met the Dalai Lama three times since taking office, each time causing a diplomatic headache between China and the United States.

White House officials said was no "specific meeting" between them to announce.

Obama has met the Dalai Lama, a political exile who has long engaged in anti-China secessionist activities in the name of religion, three times, each time leading to strong protests from China.

Though Obama will speak at the event, whether he will meet the Dalai Lama remains unclear, according to Reuters.

White House spokeswoman Bernadette Meehan said, "We don't have any specific meeting with the Dalai Lama to announce".

Washington has always been clearly aware of the potential impact of such a meeting to its relationship with China, Chinese observers said.

Yuan Zheng, a senior researcher on US foreign policy studies at the Chinese Academy of Social Sciences, said that the mystery of "to meet or not to meet" is producing ambiguity that already makes China feel unease.

The Obama administration is trying to "seek a smart balance between catering to domestic voters and controlling a potential offense to China", Yuan said.

Da Wei, a senior researcher on US studies at the China Institutes of Contemporary International Relations, observed that this time speculation began a week ahead to pave the way for "managing a publicity stunt" as well as to "cushion the blow".

"Washington is evaluating how to minimize the trauma of a meeting to the US-China relationship. And they know well that China definitely would lodge a protest," Da said.

"Because the congressional event will provide access to media, rather than offering a private occasion as in previous meetings in the White House, it may make things worse," Da said.

Meeting the Dalai Lama is a political headache that often affects China's relationship with the West because such an encounter is viewed as supporting separatism in Tibet.

Last February, Obama held a closed-door meeting with the Dalai Lama at the White House's Map Room, instead of the Oval Office.

Zhang Yesui, vice-minister of foreign affairs, summoned Daniel Kritenbrink, charge d'affaires of the US embassy in China, to lodge a protest.

"The United States, on the one hand, recognizes that Tibet is part of China and has agreed not to support Tibet independence, while on the other hand it arranged the meeting between its leader and the Dalai Lama," Zhang said.