The Rohingya crisis involving violence against the Muslim ethnic minority in Myanmar has become a challenge to Asean unity.
This week, Yangon stopped workers going to Malaysia after Malaysian Prime Minister Najib Razak criticised its treatment of Muslims. At the same time, Indonesia joined a growing chorus of concern about the fate of Myanmar's stateless Rohingya Muslims.
In his controversial speech at a rally over the weekend, Mr Najib described the violence as "genocide" and called for foreign intervention. Before that, both governments engaged in a diplomatic spat as other Asean members watched with concern.
It is apparent that the decision by Myanmar is retaliation for Mr Najib's harsh words -- a rare incident for the grouping which is known for non-interference in one another's internal affairs.
The violence in Myanmar's Rakhine State, home to many Rohingya, has sparked international criticism against Aung San Suu Kyi, with accusations flying that the Nobel Peace Prize winner has done too little to help the Muslim minority.
At least 86 people have been killed and about 30,000 displaced in a Myanmar army crackdown, launched after attacks on police posts near the Bangladeshi border on Oct 9 in which nine policemen were killed. The fresh violence affected several hundred thousand people who fled to neighbouring Bangladesh, which hastily sealed off the border.
As a Muslim-majority country, Malaysia as well as Indonesia is a large labour market for migrant workers from Myanmar. Labour-short Malaysia hosts about 147,000 Myanmar migrant workers. A large number of undocumented workers live there too.
However, some analysts have not hesitated to single out Mr Najib's move as an attempt to gain politically from the Rohingya crisis since the Malaysian leader has been battling with corruption scandals at home. He may hope that the Rohingya crisis can help restore his flagging popularity.
It should be noted that while many are pointing the finger at Ms Suu Kyi for not doing enough, some have even accused her of acting more like a politician, and forgetting her endeavours for human rights that enabled her to gain international recognition.
She deserves some credit for her attempts to seek peace in the restive state. She should be commended for doing her part in setting up a panel tasked with solving the Rohingya issue. Headed by former UN chief Kofi Annan, the panel which is formally known as the Advisory Commission on Rakhine State, is expected to make recommendations to the government in late 2017 to alleviate Rakhine's ethnic strife and impoverishment.
Ms Suu Kyi has faced limitations in running the country and is trapped by myriad problems that are a lasting legacy from military rule, among them the conflict between the Buddhist majority and Muslim minority in the restive state.
With regard to the Rohingya crisis, the two Asean members will find out sooner rather than later that the diplomatic tit-for-tat is a dangerous game that will do more harm than good to both countries and to the grouping.
While Asean is known for its motto of not interfering in one another's affairs, it may have to take precautions.
More importantly, the grouping must realise that Myanmar needs a helping hand from its regional friends to achieve a sustainable solution to its ethnic conflicts.
That should include widening access to humanitarian assistance that will improve the quality of life for both Buddhists and Muslims in Rakhine.