Western Europe is on high alert, posing travel difficulties for U.S. business owners and employees. 

Following terrorist attacks in Brussels last week, which were organized by the Islamic State, killing at least 31 people and injuring 270, the country has raised its alert to the highest level. Meanwhile, in France, a state of emergency has been extended through May, in the wake of a previous set of ISIL-organized attacks in Paris, killing 130 people in November of last year. 

The U.S. State Department describes all European countries as "potentially vulnerable" to terrorism.

"Today, the street is more dangerous than the inside of a building," said Jean-Louis Fiamenghi, head of security at Veolia, a water, waste, and energy management company based in Paris. He is also the former director the French government's anti-terrorism police force, called RAID (Research, Assistance, Intervention, Deterrance).

"Today, the new strategy of terrorists is to attack what we call 'soft targets,' whereas before, terrorists attacked symbolic locations," he says.

After Paris's November attacks, Veolia had called for greater vigilance--especially among employees traveling to foreign countries for work. Previously, on the heels of terrorist attacks at the headquarters for Charlie Hebdo, a French satirical magazine, in which 12 people were killed in January of 2015, the global energy operator had taken increased security measures--at its water production sites, for example--at the urging of the government.

Unsurprisingly, a number of U.S. travelers have expressed concern over traveling to Europe in the coming months, especially as three Americans were recently declared dead in the Brussels attacks. 

"The bomb went off in the main tourist shopping area," recalls Dianne Bush, a police officer from Crainbourne East, Australia, in a recent interview with USA Today, referring to a March 19th suicide bombing in Istanbul, Turkey. "That's a place I would surely visit." Bush had plans to travel to the city this summer, but is now having second thoughts. 

For business owners, the onus is even greater; you not only need to keep yourself safe while traveling, you need to ensure that your employees are out of harm's way, too. And if your security policy backfires, you could end up facing a lawsuit. 

"Business executives have a responsibility to their employees and co-workers when they devise travel plans," says Jim Hutton, the chief security officer with On Call International, a risk management consulting firm based in Salem, NH. "This is known as duty of care," he says. 

It's important to keep in mind that your risk management policies touch most areas of the company, including travel management and security, but also HR, legal and medical. Some common mistakes, as per the GBTA (Global Business Travel Association) Corporate Social Responsibility Toolkit, involve outlining separate policies for upper management and mid-level employees, failing to inform workers about specific travel risks (such as vaccines they'd need prior to traveling, which are recommended by the CDC,) and failing to remember that domestic travel can be just as dangerous as foreign travel. 

Have a list of communication methods set up and ready

Communicating with your employees is especially key in times of crisis, as you may decide to change your own travel policies -- for instance, some companies are now ceasing to book through particular travel agencies. Others have mandated that workers avoid staying in hotel chains with Western names, as those could become targets for terrorists.

Most importantly, you should not limit yourself to one contact method with your employees traveling abroad. 

"Don't just rely on one modality or one channel, because individual channels can be disrupted," Hutton says. He recommends using everything from Facebook to Twitter, texting, phone calls, and other international apps. Facebook, for instance, also has the global "check in" feature, where you can alert your network that you're safe in an area of crisis at the touch of a button. 

Consider the logistics involved and pack smart

If you're visiting Europe imminently, keep in mind that door-to-door travel time will likely be longer than usual. You should plan ahead for lengthy security lines at airports, fewer cabs on the streets, and fewer hotels in operation. 

Hutton says there's plenty that you can do to make your trip easier before ever leaving home. For instance, when packing your bags, consider skipping items that might look suspect to TSA officials (the order in which you pack items can similarly make the process smoother.) Make sure that your airplane ticket is current and correct, and that your passport is valid if traveling internationally.

Keep in mind that many countries will not let you enter unless your passport has at least six months of validity remaining; this is especially common in Asia, for instance in Myanmar, China, Laos, Indonesia and Malaysia. Most, but not all (25) European countries require three months of validity after exiting the country. In some cases, you may need a visa; make sure that you have the right type of visa, which depends on whether you're traveling for business or pleasure. 

Do your research before making lodging arrangements

When planning out your choice of shelter, Hutton says to be wary of sharing economy players, such as Airbnb. 

"The sharing economy has some interesting and cool platforms being developed, but you need to be choosy about those arrangements," says Hutton. "The reviews are important, [as is] having referrals from trusted colleagues."

He nods to an alleged kidnapping incident through Airbnb in August of last year, when a traveler claimed to have been held hostage by his host in Madrid, and asked to perform sexual acts. He says the host ultimately released him, though it's worth noting that Airbnb refused to call the local Spanish authorities itself, rather placing the responsibility on the customer and his mother. (The startup has since changed its corporate policies such that it will now contact the police itself, as a traditional hotel might.) 

Be wary of what you choose as transportation

Similarly, Hutton notes that "we've seen some Ubers gone wrong, some with criminal results," referring to the fast-growing ride sharing service. In one recent incident, which the police are currently investigating, a female passenger in Cincinatti alleged that her Uber driver assaulted her. 

Always when traveling, it's important to confirm your car service, if you've booked one, and that you avoid getting into unmarked taxis. 

An opportunity for innovation

As complications arise across Europe, Hutton notes that it may well be an opportunity for executives to consider new ways of conducting business.

"It's an opportunity to think differently about video collaboration," he says, rather than sending your employees into a potentially dangerous area of the world. "Think about other markets in which you can conduct the same types of meetings," he adds.

Ultimately, the most important thing is that startups remain flexible, and that you understand if and when deadlines can't get met. 

"Be truly flexible in your patience and outlook," says Hutton.