Federal Reserve officials were wary that inflation would slow further unless the US economy and labor markets also cool down, according to minutes from their July policy meeting released on Wednesday.

That means a rate hike September remains in the cards, given the robust economic activity of this summer. It's also clear that the decision won't come without a heated debate since "a couple" officials favored not hiking last month, according to the minutes, illustrating the intense debate among officials.

"Participants continued to view a period of below-trend growth in real GDP and some softening in labor market conditions as needed to bring aggregate supply and demand into better balance and reduce inflation pressures sufficiently to return inflation to 2 percent over time," the minutes said.

Policymakers hiked interest rates a quarter of a point in July.

This story is developing and will be updated.