Al-Qaeda has threatened Saudi Arabia and the United States, pledging retribution in response to Riyadh’s mass execution of several militants earlier this month, including members of the terrorist group.

On Jan. 2, Saudi Arabia executed 47 prisoners, the majority of them members of al-Qaeda, convicted of gun attacks and bombings against foreigners and securities decades ago, according to CBS News.

The mass execution has been described by various news outlets as the largest so far this century (since 1980).

In an audio recording released Monday, Ibrahim bin Hassan al-Asiri, the expert bomb-maker from the Yemen-based al-Qaeda in the Arabian Peninsula (AQAP), issued the threat. AQAP is considered to be the jihadist organization’s most potent and dangerous branch.

“Ibrahim bin Hassan al-Asiri says in a recording released by the group’s official media arm that the militants were executed because they fought ‘Crusaders’ occupying the Arabian Peninsula,” reports the Associated Press (AP). “He vowed to continue battling America and said the Saudis will be dealt with in a ‘different way,’ without elaborating.”

“By God, we will not let you go as long as there is a pulsing vein in our body,” he reportedly said, addressing the United States.

Furthermore, AQAP and its North African wing, known as al-Qaeda in the Islamic Maghreb (AQIM), also warned Saudi Arabia “will pay for the executions of dozens of its members.”

Al-Qaeda, in a Jan. 10 statement, noted that the Saudis had proceeded with the executions despite a warning against such a move.

“But they [Riyadh] insisted on offering the blood of the good Mujahideen as a sacrifice for the Crusaders on their holiday, in the New Year,” AQAP and AQIM said in the statement distributed on social media.

“Let them wait for the day when God will heal the chests of the families of the martyrs, their brothers and those who love them from the arrogant infidel,” it added.

In December, AQAP threatened to “shed the blood of the [kingdom’s] soldiers” if its fellow members were executed.

A decade ago, al-Qaeda reportedly launched a wave of attacks in the Gulf kingdom, targeting the country’s security forces and the complexes housing foreigners.

In response, the Saudis embarked upon a sweeping crackdown that largely dismantled the group, pushing some of its members to Yemen, where they formed AQAP.

“U.S. officials have long viewed the Yemeni branch as al Qaida’s most dangerous affiliate, in part because of al-Asiri’s expertise in explosives,” notes AP. “AQAP has taken advantage of the civil war in Yemen to expand its reach.”

The Islamic State (ISIS/ISIL), al-Qaeda’s Sunni rival, threatened to destroy the Saudi Arabian prisons where the 47 jihadists, including 43 members of al-Qaeda were executed on Jan. 2.

“Both organizations are fighting against Saudi Arabia, which has declared them terrorist groups and locked up thousands of their supporters,” reports Reuters, noting in an earlier report, “While Islamic State and al-Qaeda are rivals who have condemned each other on ideological grounds, they are both united in enmity towards Saudi Arabia, which has declared them terrorist groups and locked up thousands of their supporters.”

Among the 47 prisoners executed by Saudi Arabia was prominent Shiite cleric Nimr al-Nimr and four other Shiites. This has intensified sectarian tensions between the two regional rivals, Sunni Saudi Arabia and Shiite powerhouse Iran.

Earlier this month, Reuters quoted unnamed analysts as saying that the mass execution was primarily aimed at sending a message to Sunni jihadists.

“Analysts suggest Saudi Arabia was aiming to crush support for Sunni jihadists active in the kingdom without alienating more moderate Sunnis,” reports Reuters.

“Islamic State has claimed responsibility for a series of bombings and shootings in Saudi Arabia since Nov. 2014 that have killed more than 50 people, most of them [Shiites] but also more than 15 members of the security forces,” it adds.

Saudi Arabia has defended the executions saying they were part of its legitimate fight against terrorism.

“Iran and al-Qaeda aren’t the only two sources of frustration Saudi Arabia has to deal with following the mass executions. [Shiite] leaders across the region have condemned the executions and the kingdom is now waiting for the possibility of an ISIS attack which they had promised would occur should the militants be executed,” points out Headlines & Global News.