Citing potential fallout from the ongoing trade war between the U.S. and China, Jefferies analysts cut commodities price forecasts while tempering stock ratings on some miners, according to a Reuters report.

"A slowdown in construction and a decline in Chinese manufacturing and exports due to trade wars would be significant negatives for metals' demand, even if fiscal/monetary stimulus leads to some recovery in the broader Chinese economy," the Jefferies team wrote.

The move comes amid a cooldown in copper and iron ore prices, which have dropped significantly in recent trading. Iron ore prices tumbled about 11% last week to US$106.51/t, while copper dropped 4% to US$5,767/t.

Jefferies rerated Rio Tinto, BHP Group, Fortescue Metals Group Ltd., Peabody Energy Corp. and Arch Coal Inc. stocks from "buy" to "hold" and cut its iron ore fines price forecast for this year by more than 10% to US$88/t.

Other analysts also expect iron ore prices to moderate in the second half as iron ore supply comes back online in Brazil following Vale SA's Feijao tailings disaster in January. BMO Capital Markets analyst Colin Hamilton sees iron ore prices settling around US$80/t in 2019.

The trade spat between the U.S. and China has raised concerns about a global slowdown in trade. President Donald Trump recently outlined plans to put a 10% tariff on US$300 billion of Chinese goods on top of 25% tariffs on about US$250 billion in imports the U.S. imposed in three stages in 2018.

Amid the latest trade tensions between the U.S. and China, the Federal Reserve cut rates by 25 basis points last week.

Longer term, however, some analysts believe that metal prices are too low to support growth in the mining sector. Bernstein Research analyst Paul Gait recently noted that investment rates in mining are at cyclical lows, suggesting substantial upside for the sector that he expects will eventually experience a rerating.