JEDDAH, Saudi Arabia (AFP) ― Muslims began observing the holy fasting month of Ramadan on Sunday with Islamic leaders again concerned about entrenched conflicts as jihadists issued threats from Indonesia to Somalia.

Ramadan is sacred for the world’s estimated 1.6 billion Muslims because it is during that month that tradition says the Koran was revealed to the Prophet Mohammed.

The faithful fast from dawn to dusk, and abstain from eating, drinking, smoking and having sex during that time as they strive to be more pious and charitable.

In that spirit the Jeddah-based Organization of Islamic Cooperation launched a joint appeal with the Arab League for a ceasefire in Syria, where a deadly conflict has raged unabated for more than three years.

“The appeal is to stop the bloodshed of Syrians and alleviate their suffering and allow relief organizations to carry out their duties and provide urgent humanitarian assistance,” a joint statement said.

The call came as Saudi King Abdullah, whose country is home to Islam’s holiest sites, sharply criticized religious extremists and vowed not to let “a handful of terrorists ... terrify Muslims.”

Islam is “religion of unity, fraternity and mutual support” but some people “lured in by false calls ... are confusing reform with terrorism,” the monarch said.

“Their goal is to sow discord among Muslims,” he said in an apparent reference to insurgents from the Islamic State of Iraq and the Levant active in Syria and Iraq.

The radical jihadist group has spearheaded an offensive by Sunni militants in Iraq since June 9, wresting control of northern cities and capturing vast swathes of territory.

Its goal is to set up an Islamic state that straddles Syria and Iraq, and on Sunday ISIL took a step in that direction by announcing the establishment of a “caliphate.”

Meanwhile al-Qaida-linked Shebab militants warned they would step up attacks during Ramadan in the Somali capital Mogadishu, where officials deployed dozens of heavily armed police to deter violence.

Top commander Sheik Ali Mohamed Hussein said “Mujahedeen fighters will scale up strikes on the enemy” because “jihad must be intensified during the holy month of Ramadan.”

Somali President Hassan Sheik Mohamud said his government has a plan dubbed “break your fast in peace” to deter violence, while the police chief spoke of a “Ramadan security plan.”

In Indonesia, home to the world’s biggest Muslim population of about 225 million, hardliners pledged to raid bars that sell alcohol or stay open late.

The Islamic Defenders’ Front would “monitor any sinful activities in entertainment places, cafes and bars during Ramadan,” said Salim Alatas, the group’s chief in Jakarta.