Austria and Belgium's foreign ministers tested positive for COVID-19 on Saturday. The two ministers on Monday attended face-to-face talks with other EU foreign ministers in Luxembourg.
Belgium's foreign minister Sophie Wilmes said on Saturday she had tested positive.
"My COVID test result is positive. Contamination probably occurred within my family circle given the precautions taken outside my home," she said on Twitter.
Wilmes said on Friday she was going into self-isolation with suspected COVID-19 symptoms.
Austrian Foreign Minister Alexander Schallenberg has also tested positive, a spokeswoman for his ministry said earlier on Saturday.
She said Schallenberg might have caught it at the EU meeting on Monday.
"It is suspected that Schallenberg might have been infected at the Foreign Affairs Council in Luxembourg on Monday," the spokeswoman said, adding that he did not have symptoms and had been tested as a routine measure.
Schallenberg's infection raises the prospect that the EU Foreign Affairs Council was a so-called super-spreader event.
Schallenberg also attended a cabinet meeting on Wednesday but cabinet members wore masks, the spokeswoman said. Austria's cabinet had a scare less than 2 weeks ago when a close colleague of Chancellor Sebastian Kurz's tested positive.
"As a precautionary measure all members of the government will be tested on Saturday," the spokeswoman said.