As the world mourns the victims and European nations hunt for suspects linked to last week's terror attacks in Belgium, the Brussels airport is struggling to return to normalcy. Officials announced Sunday that they had not decided when to resume passenger flights out of the Zaventem airport, backtracking from previous estimates and writing that "a restart in the short term is not possible in the devastated infrastructure," according to a news release.

"In the past few days, Brussels airport has made an extensive analysis of the terminal infrastructure and of the various possible scenarios for a partial recommencement of its activities," the statement read. "When this partial restart will take place is not yet decided. That depends on the various processes that have to be restarted."

Two suicide bombers detonated their explosives Tuesday in the airport's departure hall as part of a coordinated attack by the Islamic State group. Another bomb went off in a downtown metro station, and in total at least 35 people were killed and hundreds wounded.

CNN reported that the airport resumed cargo and private flights Wednesday. Temporary construction started Thursday, but the hub was still closed to regular passengers as of Monday. Customers were urged to contact their airlines for more details in the interim.

The airport planned to start holding tests Tuesday to prepare for a partial reopening, according to Agence France-Presse. More than 800 employees were scheduled to try out its temporary check-in process.

When the airport does reopen, passengers can expect to see tight security measures "on the orders of the government," according to the release. People arriving will be transported by bus, while people departing will turn in their luggage in a different location. "The government authorities concerned must give their approval to the security system as well as to the partial recommencement of the airport activities," the release said.

Countries like the United States and United Kingdom have warned travelers to be vigilant, especially in crowded places. If you're a would-be passenger worried about traveling to Belgium in the near future, you may be able to delay your trip or receive a refund. It depends on your airline and whether you have insurance, the New York Times reported.

“Unfortunately, cancellation coverage can no longer be purchased to protect against travel to Brussels, but for travelers with an existing trip cancellation plan who are already in Brussels, trip interruption coverage might be available,” travel insurance expert Stan Sandberg told the Times.