Polish soldiers mistakenly crossed the country's border with Czech Republic in late May before setting up there, the Czech foreign ministry told CNN.
The soldiers, who had been guarding parts of the closed Polish-Czech border during the coronavirus pandemic, then started turning away Czech citizens who were attempting to visit a church in their own country.
The snafu led the Czech embassy in Warsaw to take "immediate action" and notify its Polish counterpart, the Czech government told CNN, adding that Poland has still not formally explained why it mistakenly annexed its neighbor.
"Our Polish counterparts unofficially assured us that this incident was merely a misunderstanding caused by the Polish military with no hostile intention, however, we are still expecting a formal statement," a Foreign Ministry spokesperson told CNN.
"The Polish soldiers are no longer present and our citizens can again visit the site freely," the spokesperson added.
"We are still waiting for the formal Polish statement," they repeated when asked how long Polish troops were in the country.
Poland's Ministry of Defense also acknowledged the brief occupation on Friday.
"The placement of the border post was a result of misunderstanding, not a deliberate act. It was corrected immediately and the case was resolved -- also by the