Malaysian Prime Minister Najib Razak has called on Muslim countries to lead international action over the plight of Myanmar's Rohingya Muslims.
Mr Razak made the comments in an opening statement to members of the Organisation of Islamic Cooperation (OIC) gathering in Kuala Lumpur.
The OIC is made up of 57 countries with large or majority-Muslim populations.
It is holding the emergency session to discuss what it says is a humanitarian crisis faced by the Myanmar minority.
Approximately 65,000 Rohingyas have fled Myanmar's Rakhine state since Burmese soldiers began intensive counter-terrorism operations there in October.
Describing the situation as "a cause of great and immediate concern", Mr Najib said: "Far too many people have lost their lives in Myanmar. Many have suffered appalling deaths, and those that have lived through the atrocities have witnessed or endured unspeakable cruelty. That in itself is a reason why we cannot keep silent."
The situation also threatens to create "a new home for terrorist groups", he said, as "militant elements could infiltrate and possibly radicalise this oppressed community".
What is the OIC?
Formerly known as the Organisation of the Islamic Conference, the 57-member organisation is largely made up of majority-Muslim countries.
It was established in 1969 in the wake of an arson attack by an Australian Christian on the al-Aqsa mosque in Jerusalem.
Its aims include the promotion of co-operation among member states, safeguarding Islamic holy places and working towards eradicating racial discrimination and colonialism.
But despite its size, numerous committees and stated scope, it has limited resources at its own disposal.
What is happening in Rakhine state?
After lethal attacks in October on security forces in Maungdaw district in Myanmar (also called Burma), the authorities launched a counter-insurgency operation that critics claim has involved widespread killings, rape and the destruction of Rohingya villages.
The government of Myanmar has denied the accusations and has suggested Rohingya burned their own homes down to attract international attention.
It has also prevented NGOs and international media, including the BBC, from entering the region to investigate the claims. In his speech, Mr Najib called on the Burmese government to allow humanitarian aid in.
The country's leader Aung San Suu Kyi has previously asked for "space" from the international community to deal with the issue.
After a trip to Rakhine state, former UN Secretary General Kofi Annan also said he would not describe the violence against the Rohingya as "genocide". But John McKissick, a senior official in the UN's refugee agency, told the BBC in November that Myanmar is seeking the ethnic cleansing of the Muslim minority from its territory.
Who are the Rohingya?
The estimated one million Muslim Rohingya are seen by many in mainly Buddhist Myanmar as illegal migrants from Bangladesh.
They are denied citizenship by the government despite many having lived there for generations.
Communal violence in Rakhine state in 2012 left scores dead and displaced more than 100,000 people. They face widespread discrimination and mistreatment.