The number of US import restrictions so far this year has already surpassed half of last year's total, a local trade body said Monday, including one against South Korean products.

According to the Korea International Trade Association (KITA), the US has launched an investigation into 24 separate cases on suspicions of anti-dumping and countervailing duties in the January-April period. This is already more than half of the 53 actions taken for the whole of 2016.

South Korean carbon and alloy steel wire rods were included in an anti-dumping probe.

The number of new US import restrictions increased and decreased each year, from 16 in 2012 to 57 in 2013, 37 in 2014 and 64 in 2015. China was the most affected with 153 probes currently underway. India was next with 32 and South Korea has 24.

Trade officials say that on top of such investigations, the US is using other tools to levy heavier punitive duties. The Adverse Facts Available (AFA) regulation is applied to companies deemed as not faithfully submitting information requested by the US government. The US Commerce Department has invoked AFA on 60 of the 247 investigation cases of foreign firms from 2015.

The average tariffs on 41 such cases involving market economy countries was 52.28 percent.

The Commerce Department is also employing "particular market situation" regulations that allow for high tariff rates on goods from countries  where export prices are believed to have deviated from those of the domestic market. The regulation was invoked on oil country tubular goods from South Korea to slap higher tariffs than the preliminary duties set in October. (Yonhap)