On March 15, 2020, a group called League of the Revolutionaries claimed responsibility for the March 12 rocket attacks on the Taji military base north of Baghdad that killed three members of the U.S.-led international coalition in Iraq.
The formation of this group appears to be part of a new tactic by Iran to distance itself and its Iraqi proxies from the rocket attacks on U.S. targets, and ultimately increase the pressure on U.S. troops in order to ensure their departure, based on the Iraqi parliamentary decision to end their presence following the January 3, 2020 airstrikes that killed Iran's Islamic Revolutionary Guard Corps (IRGC) Qods Force commander Qassim Soleimani, or at the very least drag them into a military confrontation with its proxies inside Iraq far from Iran's borders.
This Operation Was "Only The Beginning, And The End Is Soon To Come"
In a two-minute video statement that surfaced online on March 15, the League of the Revolutionaries opened with a Quranic verse often used by extremist Islamists to express threats and warnings in connection with an ongoing state of hostility: "Fight them; Allah will punish them by your hands and will disgrace them and give you victory over them and satisfy the breasts of a believing people."
The statement said: "After Allah empowered us against our American enemy, and after we gathered accurate information about its vital targets, it was imperative that we give them a taste of our missiles, our courage, and the strength of our resolve."
Accusing the U.S. of violating Iraqi sovereignty, it said: "The American enemy is an enemy of all the vulnerable people, and it has gone too far in violating Iraq's sovereignty and its people's dignity. We shall not accept humiliation and prostration as long as we have a pulse in our veins."
In a clear reference to the January 3 U.S. drone strike that killed IRGC Qods Force commander Qassem Soleimani and Popular Mobilization Units (PMU) deputy commander Abu Mahdi Al-Muhandis, the statement said that the missile attack on Taji base is in line with the group's retaliation for "the assassination of our martyr leaders, which left a sigh in the chests that will not go away until the occupied forces leave in humiliation."
About the decision to claim responsibility for the attack, it explained that this was in response to a request by Kat'ib Hizbullah, which had, in an earlier statement, called on those who carried out the Taji base attacks to reveal their identities and pledged to protect them. 
"In response to our Mujahideen brothers' request, we say that although our history in the resistance is new, we want to state for the record that we are the first to strike the occupier. We hereby announce that these blessed operations, i.e. the striking of the bases of the occupier, are ours alone, and we are not afraid to announce this."
Stressing that the rocket attacks on Taji base were "only the beginning, and the end is soon to come," the statement further warned Iraqi officials who condemned the attacks: "To the agents of the [U.S.] embassy, we say that your days are numbered."
The New Group – Part Of The Iran-Backed Factions
The design of the emblem of the group, which was on the statement, is similar to the emblem used by Kata'ib Hizbullah and other Iran-backed Shi'ite factions in Iraq that have been escalating threats against U.S. forces since late December 2019.
Reports in Arabic-language media noted that this group is most likely an affiliate of Kata'ib Hizbullah, suggesting that the formation of the League of the Revolutionaries serves the agenda of these factions, as it will enable them to carry out attacks in secret and repudiate them in public, to avoid being blamed for them by Iraqi authorities and to avoid being held accountable by the U.S.
This Iranian tactic was used before; following the 14 September 2019 attack on Aramco facilities in Saudi Arabia, the Houthis issued a statement of responsibility for the attack – yet the attack had come from the north, from Iran.
The new group's emblem
Iran's New Operational Structure In Iraq
Politically, this new hit-and-run tactic of the Iran-backed factions supports Tehran's efforts to spare its favorite Iraqi politician Adel Abdul Mahdi from any embarrassment that these attacks could cost him, now that Iran-backed factions and MPs are pushing to reinstate him as a prime minister. Earlier, he had not issued any official statement condemning the rocket attack on Taji base, as President Barham Saleh or parliamentary speaker Muhammad Al-Halbosui had.
Although his term as Iraq's caretaker prime minister ended weeks ago, Abdul Mahdi is still holding ministerial meetings. In fact, the Iraqi media reported that he had a meeting with security authorities at which re he instructed them to investigate the attack, however no statement of commendation has been published.
Iran is pushing for Iraqi politician Adel Abdul Mahdi, right, to be reinstated as prime minister (source: Shafaaq.com)
A recent report in the Lebanese daily Al-Akhbar, which is close to Lebanon's Hizbullah, suggested that the "restructuring" of the Iraqi factions is part of Tehran's plan to establish "new cells" linked to its IRGC Qods Force so as not to embarrass its political allies in Iraq. At the same time, this would increase both political and military pressure on U.S. troops, and ultimately increase the chances of a military confrontation between Iraqi armed factions and U.S. troops far from Iran's borders.
Al-Akhbar further cited "Iraqi security sources" as saying that Washington has been pressuring Iraqi government to install the Patriot air defense system in order to shoot down rockets targeting U.S. troops in Iraqi bases. The rocket attacks on Taji base, it added, were targeting a site where this air defense system would be located. The sources also told the Lebanese daily that Iraqi intelligence is concerned the that a U.S. withdrawal would encourage ISIS to step up the attacks, something that Iran-backed factions in Iraq believe it is a blackmailing card that the U.S. is threatening to use in order to extend its presence in Iraq.
 Youtube.com/watch?v=9HTejcpJJq4, March 15, 2020.
 Quran, Surat Al-Tawab, Verse 14.
 See MEMRI JTTM report Kata'ib Hizbullah Praises Taji Missile Attack As 'Jihadi Operation,' Asks Those Responsible For It To Identify Themselves, Denounces Iraqi Officials For Condemning It, March 12, 2020.
 Alakhbar.com, March 13.2020.