Residents stock up necessities at a supermarket in Manhattan of New York, the United States, Jan. 22, 2016. (Photo: Xinhua)

Tariff tensions have sent US consumer confidence to a near two-year low, a business research group said on Tuesday.

The Conference Board's consumer confidence index, a key measure of the US economy, slipped to 121.5 in June, the lowest since September 2017. The May reading was 131.3.

The group's present situation index, which is based on consumers' assessment of current business and labor market conditions, decreased from 170.7 to 162.6. The decrease was driven by a less favorable assessment of business and labor market conditions.

The expectations index, which is based on consumers' short-term outlook for income, business and labor market conditions, decreased from 105.0 last month to 94.1 this month.

Lynn Franco, senior director of economic indicators at The Conference Board, said in a statement that the escalation in trade and tariff tensions earlier this month appears to have shaken consumers' confidence.

"Although the Index remains at a high level, continued uncertainty could result in further volatility in the Index and, at some point, could even begin to diminish consumers' confidence in the expansion," said Franco.

According to the group's survey, the percentage of consumers expecting business conditions will be better six months from now decreased from 21.4 percent to 18.1 percent, while those expecting business conditions will worsen rose from 8.8 percent to 13.1 percent.