Syria is coming under increasing international pressure after European leaders and US President Barack Obama issued a statement calling for president Bashar al-Assad to step down.

But after weeks of a heavily reported brutal crackdown that has doubtless killed hundreds of protesters, many are asking why the statements from Western nations only came now.

Protests which began five months ago have seen Syrian forces carry out violent suppression of demonstrators, leaving 1,800 civilians dead according to human rights groups.

Rosemary Hollis, a professor of Middle East policy studies at City University, London says it is not a surprise it has taken countries so long to publicly call for Assad to go after the war in Libya.

“They were not going to be in a hurry with Syria or indeed with Yemen. The reactions you're getting today come within the context of what's happened this year. Libya was the turning point - just siding with the rebels doesn't do the job.”

Hollis says there is no “neat divide” between president Assad’s regime and everyone else in Syria, and the potential of an even more despotic ruler replacing him was one reason why the West was quiet for so long.

“If Syrian society is not united either behind him or against him, how do you identify an alternative?" she said.

“The situation in Syria as well as in Yemen is not as straightforward as it was in Egypt, Tunisia and even Libya. Because a lot of the population in Syria have continued to support Assad for fear of the alternatives.”

“Instead there's three or four segments to the division in Syria. It's not the regime and everybody else. There is a real genuine fear that there could be sectarian fighting.

"It's exactly like Iraq in the sense that Syrians keep saying 'we're all secular, there's no particular divides' and then when the regime crumbles it also emerges that the population divides along particular lines, Shia versus Sunni, Christians etcetra.”

Ziya Meral, a research associate at the Foreign Policy Centre agrees saying the potential for sectarian conflict meant “everyone was afraid that what might replace the regime would be worse”. But he says now violence has reached an “unbearable” level and patience has run out”.

The UN have said Syria’s crimes against its citizens "may amount to crimes against humanity".

For Hollis, Western leaders have spoken out not because they think they have the moral highground but because they think Assad can no longer "handle the situation" in Syria.

“The moral highground came into view briefly when you saw armoured vehicles pounding down the road in Libya towards Behnghazi [and the West intervened to prevent a massacre] ... that was only a moment in many months of complex developments. To identify the correct moral position at any one time isn't easy.”

She added: “Essentially, their reading of the situation is he can't handle the situation so he's not going to be able to correct the problem and his behaviour is such that they cannot with a straight face go on without condemning it totally.”

For Meral, the countries’ public declaration against Assad is a “positive action” but it will only be meaningful if it is followed by sanctions.

He says, however, that whilst some Arab states have condemned Syria massacring its own people, its regional ally Iran is unlikely to follow their lead.

“If Iran comes up condemning Syria than that would be the most shocking. It's not going to happen, Iran needs Syria to expand its influence across the region, by having influence in Lebanon and Syria Iran is able to threaten a lot of countries."