The United States has designated the al-Mulathamun Battalion as a terrorist organization and an associate of a Lebanese-based group as terrorist, the State Department said on Wednesday.

With the designations, the US prohibits against supporting or engaging in transactions with the al-Mulathamun Battalion and Usamah Amin al-Shihabi and freezes all their property in the country, according to two separate statements issued by the State Department.

A sub-battalion of the al-Mulathamun Battalion, named "Those Who Sign in Blood," claimed responsibility for the attack against a gas facility in Algeria in January that killed at least 38 civilians, including three US citizens, one statement said.

The US also held the group responsible for twin suicide bombings in Niger in May, which killed at least 20 people.

Originally part of al-Qa'ida in the Islamic Maghreb (AQIM), the al-Mulathamun Battalion became a separate organization in late 2012 after its leader Mokhtar Belmokhtar split from AQIM.

In August, the al-Mulathamun Battalion merged with another group under the name "al-Murabitoun". The new group "constitutes the greatest near-term threat to US and Western interests in the Sahel," said the statement.

Al-Shihabi is an associate of FAI, a Lebanese-based militant group formed in 2006, whose ultimate goal is the institution of Islamist sharia law in the Palestinian refugee camps and the destruction of Israel, said another State Department statement, adding that Al-Shihabi at times has played a key leadership role in FAI.

He has also recently been appointed head of Syria-based al- Nusrah Front's Palestinian wing in Lebanon. Al-Nusrah Front was formed by al-Qa'ida in Iraq in late 2011, according to the State Department.