Walmart Inc. said it is restricting all cross-border international travel and canceling a conference in Dallas due to the escalating coronavirus outbreak.

The world’s biggest retailer said in a statement that it was limiting cross-border international travel in all markets it operates to just “business-critical” trips and that such travel must get approval. For employees currently traveling, Walmart advised them to make plans to return.

The company also curbed domestic travel to only “essential operations,” and will restrict less essential travel for conferences and trade shows, it said. The new guidelines will extend through at least April, it said.

The retailer is also canceling the Walmart U.S. Customer Conference scheduled in Dallas next week. It will have a virtual form of the meeting instead, it said.

“It seems best to cancel given the size of that meeting, plus the benefit of having our store managers present in their stores during this time,” it said in the statement. Within its offices, staff will still gather in groups for meetings but Walmart said employees should not travel for them. Employees should not to come into work if they are feeling unwell, it said.

Walmart will evaluate its response, which did not reference any potential U.S. store closures, in the coming weeks and months, as more is learned about the virus, it said.