When asked whether there would be a Fort Trump in Poland, Shanahan told reporters, "Well, that's a great question. Why don't we let President Trump make any announcement like that?"
"The construction is continuing. There were some delays that we encountered. But we've got a recovery plan in place that's being executed, and the Missile Defence Agency is supervising that," Shanahan added.
A senior US administration official told reporters on Tuesday that Trump and Polish President Andrzej Duda will make a significant announcement on Wednesday about enhancing deterrence posture in Europe.
The Financial Times reported earlier in June that the United States and Poland are close to inking a deal on increasing the number of US troops stationed in the Eastern European country by at least 1,000. Last year Trump said the United States was considering establishing a permanent military base in Poland.
The Polish president will be in Washington on Wednesday to discuss a range of bilateral interests including security, trade, energy, and deepening the security partnership, the official said.