U.S. Commerce Secretary Wilbur Ross recommended Friday that President Donald Trump consider imposing curbs on steel and aluminum imports, a move apparently targeting China but which could affect Japan and other exporters.

As part of the proposed measures to safeguard U.S. "national security," Ross called for a new global tariff of at least 24 percent on all steel imports, as well as another blanket tariff of at least 7.7 percent on all aluminum imports.

Trump will make a decision on steel import curbs by April 11 and on aluminum restrictions by April 19, according to the Commerce Department.

U.S. investigations "found the quantities and circumstances of steel and aluminum imports 'threaten to impair the national security,'" a department report said, citing excessive imports and global production overcapacity driven partly by Chinese government subsidies.

"Free markets globally are adversely affected by substantial chronic global excess steel production led by China," the report said.

"A major cause of the recent decline in the U.S. aluminum industry is the rapid increase in production in China," it said. "For example, there is only one remaining U.S. producer of the high-quality aluminum alloy needed for military aerospace."

The Chinese Commerce Ministry, in a statement, said the findings of the U.S. investigation "have no basis and are totally inconsistent with the facts."

The ministry urged the United States to refrain from unilaterally restricting trade on ill-defined national security grounds, saying if other countries were to follow that example, "it would have a serious impact on the international trade order."

"If the final decision of the United States affects China's interests, China will definitely take the necessary measures to safeguard its legitimate rights," it said.

The proposed measures are intended to lift U.S. production to 80 percent in both industries. At present, domestic steel plants are running at 73 percent of capacity and aluminum plants at 48 percent.

Ross told reporters on a conference call that proposed measures do not violate global trade rules as the World Trade Organization recognizes import curbs on national security grounds.

Trump could determine that certain countries should be exempted from the proposed curbs "based on an overriding economic or security interest of the United States," the report said, suggesting he may exclude allies such as Japan and North Atlantic Treaty Organization countries from any action.

"The president may take a range of actions, or no action, based on the analysis and recommendations," it said. "Action could include making modifications to the courses of action proposed, such as adjusting percentages."

In 2017, Japan exported an estimated 1.78 million tons of steel products to the United States, making it the seventh-largest exporter, according to Commerce Department data.

China was the 11th-biggest exporter, but it ships steel to the United States via other countries as well, leading the department to propose import restrictions from a broader range of countries.

As for steel, Ross recommended that Trump consider three options including the imposition of a 24 percent global tariff on all imports.

Another is a tariff of at least 53 percent on all imports from 12 countries -- Brazil, China, Costa Rica, Egypt, India, Malaysia, Russia, South Africa, South Korea, Thailand, Turkey and Vietnam.

The third option involves a quota on all products from all countries equal to 63 percent of their 2017 exports to the United States.

On aluminum, Ross presented three options including the 7.7 percent global tariff on all aluminum imports.

He also proposed a quota on all imports from all countries equal to a maximum of 86.7 percent of their 2017 exports to the United States.

The third involves a tariff of 23.6 percent on all products from China, Hong Kong, Russia, Venezuela and Vietnam, while all the other countries would be subject to quotas equal to 100 percent of their 2017 exports to the United States.

U.S. Senate Democratic leader Chuck Schumer welcomed the proposed import curbs, saying they "are the beginning of efforts by this administration to finally get tough on China."

Schumer said in a tweet that he hopes the measures will level the playing field for American steel and aluminum producers and workers.