High growth rates in China and the United States offer positive economic opportunities for Botswana, an International Monetary Fund (IMF) leader said Thursday.

"There is a pickup in diamond prices, and sales and production are on the rise," Deputy Managing Director of the IMF Zhang Tao said during a luncheon hosted by Bank of Botswana in the country's capital Gaborone.

As China and the United States, the top diamond jewelry markets, see rapid economic growth, Zhang said the IMF is cautiously optimistic about Botswana, a leading producer of diamonds around the world.

"We expect a rebound in growth this year and next to about 4.5 percent - rising further to 5 percent over the medium term," he explained.

As of now, global growth is projected by the IMF to remain unchanged, compared with its April forecasts, at 3.9 percent this year and next. The IMF, however, believes that downside risks have increased.