Boston University announced in a memo Friday it will prohibit all University-sponsored domestic and international travel for students, staff and faculty — but some parties may be eligible for situational exemptions.

The University will also deny the public access to campus, unless they receive permission, and limit the spaces family and friends can visit, according to the memo.

Graduate students as well as faculty and staff, however, may be granted exceptions to the domestic no-travel ruling. Graduate students are eligible to petition their college’s dean, and faculty may seek approval from an appropriate administrator, the memo stated.

Graduate students can also petition for an exception to the international travel ruling with the support of their college dean. Petitions will be considered by BU’s Global Travel Risk Assessment Committee. 

Rachel Lapal, assistant vice president of Public Relations at BU, wrote in an email that graduate appeals are reviewed on a case by case basis and depend on the student’s individual circumstances.

The memo stated that although Massachusetts is seeing some success in alleviating the spread of the coronavirus, this is not yet the case everywhere.

“While trends in Massachusetts, surrounding states, and some countries indicate a move toward gradual reopening, the same is not true in many parts of the US,” the memo reads. “The situation in much of the world remains highly uncertain.”

Lapal wrote that these policies will be reevaluated over time, and that the University will ensure its rules meet public health standards outlined by local and national government.

“Travel guidance may be modified if travel policies and guidelines at a state and federal level change,” Lapal wrote.

BU is also restricting spaces and facilities on campus to only students and employees, according to the memo. University buildings will be closed to non-affiliated individuals during the semester.

Signs across campus will communicate this policy to the public, Lapal wrote, and building coordinators will work with departments to ensure everyone understands expectations.

Construction contractors, vendors and outside faculty or researchers are also among those who must first be invited by a University host before gaining approval to come to campus. Hosts include registered student organizations, employees and BU departments or offices.

Students can invite visitors from outside of BU, the memo states, but they will only be permitted in the lobbies of student residences. Guests are not allowed to enter campus buildings or stay overnight.

Any tenants leasing a University residence may receive visitors — or employ delivery services, suppliers or contractors — if granted approval from BU Real Estate, who will serve as the host.

Tenants who regularly interact with students, faculty or staff may be included in the COVID-19 testing and contact tracing program administered by the University. Those who must comply are determined by the Provost and Senior Vice President of Operations.

All visitors will be required to comply with the University’s health protocols, which include monitoring any illness symptoms prior to visiting campus.