WASHINGTON — The Federal Reserve raised interest rates on schedule during the first half of 2017, but its plans for the second half of the year are less clear, according to minutes of the Fed’s most recent meeting in June.

Officials debated how soon to start reducing the Fed’s securities portfolio, as the sluggishness of inflation and the exuberance of investors continued to concern them.

At the June meeting, the Fed raised its benchmark interest rate for the third consecutive quarter, to a range between 1 percent and 1.25 percent. It also published a plan for paring its substantial holdings of $4 trillion in Treasuries and mortgage-backed securities, acquired after the financial crisis to further reduce borrowing costs for businesses and consumers.

The Fed has said that it wants to begin the balance sheet plan this year. The minutes of the June meeting said several officials wanted to start “within a couple of months,” while others favored waiting, suggesting that officials are debating whether to begin in September or wait until December. The Fed published the meeting account Wednesday after a standard three-week delay.