Afghan operations will be the main topic in a NATO meetings in Maastricht, Netherlands, and issues such as Russia, missile defense, Kosovo and Georgia will be discussed in Brussels, Belgium, Pentagon spokesman Geoff Morrell said Tuesday during a news briefing.
Gates was to depart for Europe Tuesday night.
"They will discuss a range of organizational and security issues confronting the alliance," Morrell said. "But as you might expect, the NATO operations in Afghanistan will likely dominate their discussions."
The secretary first will visit Maastricht for a meeting of defense ministers with troops in Afghanistan's Regional Command South, Morrell said. Gates will then attend the quarterly NATO defense ministers conference at the alliance headquarters in Brussels on Thursday and Friday.
About 56,000 U.S. service personnel are deployed in Afghanistan; that number is projected to increase to 68,000 by the end of year. The 33,000 NATO and allied troops stationed in Afghanistan is expected to increase to 35,000.