The U.S. patient recently diagnosed with Ebola flew through Brussels on his way to Texas, Canada’s top health leader said Wednesday. 

The Canadian official’s statement raises alarms for Europe and increases pressure on the U.S. to release more details on the infected patient’s path from Liberia. 

The patient, whose identity has not been released, also passed through another airport, as there are no direct flights from Brussels to Dallas.   

Centers for Disease Control and Prevention (CDC) director Tom Frieden said on Tuesday that the patient, a man, had flown from Liberia on Sept. 19. He declined to release other details about the flight because he said there was “zero risk of transmission” onboard.

The man was living with family in the U.S. for about a week before he was diagnosed and quarantined in a Dallas hospital. He began showing symptoms Sept. 24, health officials said.

U.S. airlines are growing anxious in the wake of Tuesday’s diagnosis. It is the first Ebola case ever reported in the U.S.

Airlines for America, a national trade group, said Wednesday that it is in close contact with the CDC.

More than 200 flights to the affected area in Western Africa have already been canceled by airlines including British Airways, Emirates airlines and Kenya Airways.

Brussels, a frequent spot for connections from Africa, has been on high alert throughout the outbreak.