The disclosure that Germany is to stay away from the games' opening ceremonies in August could encourage President Nicolas Sarkozy of France to join in a gesture of defiance and complicate Gordon Brown's determination to attend the Olympics.
Donald Tusk, Poland's prime minister, became the first EU head of government to announce a boycott on Thursday and he was promptly joined by President Václav Klaus of the Czech Republic, who had previously promised to travel to Beijing.
"The presence of politicians at the inauguration of the Olympics seems inappropriate," Tusk said. "I do not intend to take part."
Frank-Walter Steinmeier, Germany's foreign minister, confirmed that Merkel was staying away. He added that neither he nor Wolfgang Schäuble, the interior minister responsible for sport, would attend the opening ceremony.
Hans-Gert Pöttering, the politician from Merkel's Christian Democratic party who chairs the European parliament, encouraged talk of an Olympic boycott this week and invited the Dalai Lama to address the chamber in Strasbourg, while another senior German Christian Democrat, Ruprecht Polenz, said a boycott should remain on the table.
"I cannot imagine German politicians attending the opening or closing ceremonies [if the Tibetan crackdown continued]," he said. Merkel enraged the Chinese leadership a few months ago by receiving the Dalai Lama in Berlin for private talks.
Brown is to meet the Tibetan spiritual leader when he visits Britain in May, but is determined to be in Beijing. "We are fully engaged in supporting the Olympics," said David Miliband, the foreign secretary. "We want to see it as a success, and I think it's right that the prime minister represents us."
While announcing that German leaders were staying away from Beijing, Steinmeier denied they were boycotting or staging a political protest against the Chinese military and police campaign in Tibet and surrounding areas.
While expressing scepticism about a complete boycott, he did not rule one out. "This is not the right moment to talk about a boycott ... We should watch how the Chinese government deals with the situation in the next weeks and months."
If Merkel and others do not attend the opening ceremony, it is likely to reinforce a growing sense in China that the Olympics is being used to vilify the host.
China had hoped to use the games to highlight its economic development and growing openness. But it is increasingly proving an opportunity for critics to bash China's one-party political system, human rights abuses, treatment of minorities and tightly controlled media.
The Tibet crisis has been pushed on to the agenda of a meeting of European foreign ministers in Slovenia, with the French, who will be presiding over the EU during the Olympics, calling for a team of European officials to be dispatched to China on a fact-finding mission.
British and US diplomats were among a group of outside officials allowed to travel yesterday to Lhasa, the Tibetan capital, for the first time since the crisis erupted a fortnight ago.
The EU foreign ministers are to discuss the China quandary at lunch in Slovenia today, with calls being made for a common European position.
"We don't support a boycott and don't intend to boycott the opening of the games," a British Foreign Office spokesman said. "None of the 27 [EU states] are calling for a boycott yet."
The French foreign minister, Bernard Kouchner, has described the boycott proposal as "interesting", while Sarkozy this week hedged his bets and said his attendance depended on China's conduct.