Dhaka: A total of 54 countries, including five Arab states, have pledged to join the US-led fight against Islamic State (IS) militants which began in Syria on Tuesday. President Obama has asked for UN support in the resistance against the militants.A meeting regarding the operation against IS was held in New York yesterday, Wednesday. Bangladesh was invited to attend. However, Foreign Minister Abul Hasan Mahmud Ali declined to attend. Though Bangladesh has taken a clear stand on the war against terrorism, it has not taken a decision as yet about joining the alliance against IS.Obama two weeks ago announced the plans for a greater alliance to tackle IS.Analysts have their doubts about the sustainability of this alliance. The US President has already said that this war may continue for years. Members of the alliance too may face both civil and military losses.According to the US State Department, 54 countries have committed to the fight against IS. These include the tiny state of Andorra to a country like Ukraine which is fighting pro-Russian rebels in its eastern region. Five Arab states have directly joined and supported the US attack in Syria from the very outset. These are Saudi Arabia, UAE, Jordan, Bahrain and Qatar.Meanwhile, Washington's European allies, Britain and France, are being more cautious about joining the alliance.