The State Department said it was classifying the BLA as a global terrorist group, making it a crime for anyone in the US to assist the militants and freezing any US assets they may have.
The United States on Tuesday designated militants fighting the Pakistani state in Balochistan as terrorists after it carried out deadly attacks targeting Chinese interests.
The State Department said it was classifying the Balochistan Liberation Army (BLA) as a global terrorist group, making it a crime for anyone in the United States to assist the militants and freezing any US assets they may have.
The BLA "is an armed separatist group that targets security forces and civilians, mainly in ethnic Baloch areas of Pakistan," the State Department said in its designation.
The outfit was already recognised as a terrorist group by Pakistan and the UK.
Pakistan has been fighting the militants in the southwestern region since 2004, with the militants recently finding a new focus in rallying against China's investment that is part of its major Belt and Road initiative.
The BLA has targeted China in Pakistan multiple times, including a brazen daylight attack on the Chinese consulate in Karachi that killed four people in November.
In May, five people including a soldier were killed after gunmen stormed the only five-star hotel in Gwadar, the port city which Pakistan is hoping to develop into a major commercial hub.
The BLA, lead by Harbiyar Marri, had claimed responsibility for the deadly attack.
Marri, who lives in exile, served as a Member of Balochistan Assembly between 1997 and 1999. His father and other family members have also served in key positions in the government in the past.
Pakistan has been accused of widespread human rights violations in its crackdown in Balochistan.
Pakistan denies wrongdoing and says its historic rival India of is fomenting the insurgency. New Delhi denies any support.
The US designation of the group comes despite vocal concerns by Washington over the Belt and Road Initiative, with Washington accusing China of imposing debt traps on developing nations.