Islamist and jihadi organizations encourage their followers to carry out violent attacks on Ramadan, the holiest month for Muslims, when terrorist groups especially encourage and value martyrdom.

There is usually a spike in jihadi attacks during the holy month, expected to start on Friday this year.

Following the Islamic State’s (ISIS/ISIL) call for violence during the holy month last year, the U.S. State Department-led Overseas Security Advisory Council warned: “According to Islamic practice, sacrifice during Ramadan can be considered more valuable than that made at other times, so a call to martyrdom during the month may hold a special allure to some.”

The Middle East Media Research Institute (MEMRI) notes that Islamist and terrorist groups stress themes of jihad in messages, articles, and sermons published on Ramadan.

Among the Ramadan themes identified by MEMRI, are:

The commandment of jihad, which is of supreme importance at all times, assumes even greater importance during this holy month and gains precedence over all other commandments… On Ramadan Allah grants fighters special strength, despite – or rather by virtue of – their fasting. Those who gain martyrdom during the month of Ramadan are doubly rewarded in Paradise.

Most Muslims follow the tradition of abstaining from eating, drinking, smoking, having sex, and other physical needs each day, starting from before the break of dawn until sunset during the month of Ramadan.

However, other Muslims adhere to the tradition that perceives Ramadan as a month of jihad and martyrdom.

Islamic extremism-affiliated terrorists killed at least 420 people and wounded nearly 730 others across the world during the Muslim holy month in 2016, described as one of the bloodiest in modern history.

MEMRI describes Ramadan as “a month in which Allah grants military victories to His believers,” a belief exploited by jihadist groups like ISIS.

“It was during Ramadan that Muslims triumphed in many of their battles… Given the historic religious and military significance of Ramadan, Islamist and jihadi groups, and sometimes also mainstream Arab organizations and Arab media, escalate incitement to jihad and martyrdom during this month,” it adds.

In its annual call for violence during the holy month last year, ISIS declared, “Ramadan, the month of conquest and jihad… make it a month of calamity everywhere for the non-believers.”

The terrorist group encouraged Muslims to carry out violent attacks against civilian and military targets “to win the great award of martyrdom.”

Jihadist groups did not spare the Prophet’s Mosque, one of Islam’s holiest sites where the Prophet Muhammad is buried, during Ramadan 2016.

On July 4 of last year, Islamic terrorists killed at least four security officers and injured seven others in a suicide attack at the mosque, located in Saudi Arabia’s Medina, the holiest city in Islam after Mecca.

In an assessment of Ramadan 2016 published by Al Arabiya, Sigurd Neubauer, a non-resident fellow at the Arab Gulf States Institute in Washington, pointed out, “While these attacks remain unclaimed, the bombing near one of Islam’s most sacred sites, during its holiest month, has brought some additional clarity to international observers: Militants do not distinguish between Muslims or Westerns when it comes to killing civilians.”

An ISIS-linked jihadi carried out the biggest act of domestic terrorism in the United States since 9/11 during Ramadan last year, killing at least 49 people and injuring more than 50 others at a gay nightclub in Orlando, Florida.