The U.S. State Department has approved the potential sale of Volcano anti-tank mine laying systems to Taiwan for an estimated price of $180 million, the Pentagon announced on Wednesday. Northrop Grumman and Oshkosh are the primary contractors for the potential sale. According to U.S. law, the executive branch has to notify the COngress of potential arms sales that are over a certain amount. But these notifications are usually not made unless lawmakers have given the State Department and Pentagon informal approval to move ahead.

The potential sale comes amid China’s increased military presence and drills around Taiwan to assert its sovereignty claims over the island. Chinese air force missions are carried out almost daily near the island over the past three years.

Taiwan’s defense ministry said in a statement that the sale would take effect in about a month and it would help boost the island’s “asymmetric warfare” capacity to make its forces more agile.

“The Chinese Communist Party’s frequent military activities near Taiwan have posted severe military threats to us,” the ministry said, adding that continuous U.S. military sales are the “cornerstone of maintaining regional stability and peace.”

The United States is Taiwan’s strongest international backer and main arms supplier, which angers China.