Members of the ruling Democratic Party reacted strongly to a US proposal to impose a massive tariff on South Korean steel imports, saying the country should consider retaliatory measures, such as restrictions on American agricultural imports.

The US Commerce Department suggested last Friday slapping a 53 percent tariff on steel imports from a dozen countries, including South Korea, as part of measures to protect the local industry. The proposal came after the US imposed steep tariffs on imports of Korean washing machines and solar cell panels.

On Monday, President Moon Jae-in ordered the government to deal with such "unfair protectionist trade measures" in a "confident and resolute" manner, raising concerns that the two allies could clash head-on over trade issues.

The ruling Democratic Party also showed a tough reaction to the US move.

"I express strong regret over the unilateral and dogmatic measure and the wrong retaliatory tariff must be scrapped immediately," Rep. Woo Won-shik, the ruling party's floor leader, said during a party meeting.

"We have to look closely into whether a series of US measures to strengthen trade barriers are not in violation of World Trade Organization rules, and we should actively consider corresponding retaliatory measures."

Woo also said it is a far-fetched claim that civilian steel imports pose a threat to the US.

Rep. Hong Ihk-pyo, the party's deputy chief policymaker, was more specific about retaliatory measures.

"The US trade pressure has crossed the line," Hong said. "We also have to strengthen quarantine inspections on agricultural and livestock products. I think we can take considerable measures against American agricultural and livestock products."