Treasury officials on Thursday imposed sanctions on three companies, two based in China and one in Lebanon, accused of being fronts used to obtain technology and equipment to build drones for Hezbollah.

Another Chinese company and its owner were sanctioned for procuring electronic components used by Yemen's Houthi rebels to build roadside bombs. The rebels are fighting a Saudi-led intervention aimed at restoring the internationally recognized government of Abd Rabbuh Mansour Hadi.

"Hizballah is a dangerous, destabilizing terrorist group, and Treasury is determined to maintain maximum pressure on this organization by targeting its many revenue streams," Adam Szubin, the acting undersecretary for terrorism and financial intelligence, said in a statement, using one of the alternate spellings for the Islamist militant group. "Today's action highlights Hizballah's exploitation of the commercial sector to support its military capabilities and facilitate acts of terrorism."

Drones are a particularly dangerous addition to Hezbollah's arsenal, dating back to the first ones obtained from Iran in 2004. The Lebanese Shiite Muslim militia regularly sends flights into Israel, including an October 2012 mission aimed at Israel's nuclear complex at Dimona that may have been able to capture images of the site. The group also has used the remotely-piloted aircraft to attack Syrian rebel bases on behalf of the government of President Bashar Assad.

In April, IHS Jane's Defence Weekly revealed that the group had constructed an airstrip in Lebanon's Bekaa Valley for drone operations.

Treasury's designation targets Beirut-based Vatech SARL and its owner, Fadi Hussein Serhan, who "has purchased unmanned aerial vehicles and accessories, and various electronic equipment from companies in United States, Europe, Asia, and the Middle East" on behalf of Hezbollah.

Also designated were the Chinese companies Aero Skyone Co. Limited and Labico SAL Offshore, which are owned by Ali Zeaiter, who was designated in 2014 as a Hezbollah procurement agent for using another front company to purchase communications, electronics and navigation equipment for use in the group's drone program.