BEIRUT - Syria declared Morocco's ambassador persona non grata on Monday, the foreign ministry said, in a tit-for-tat move hours after Rabat expelled Damascus's envoy to the North African country.

"Syria has just considered the accredited Moroccan ambassador to Syria persona non grata," ministry spokesman Jihad Makdissi said via Twitter, after Morocco demanded that Syrian ambassador Nabih Ismail depart the country.

In its statement announcing Ismail's expulsion, Rabat cited violence in Syria as the trigger for its decision.

"The Moroccan authorities have been following with great concern the violence that Syria's people are suffering," it said, putting the death toll in Syria at 20,000.

The expulsion followed the defection last week of Syria’s ambassador to Iraq and the flight the week before of a prominent general once close to Assad - developments that Western officials said showed that Syrian President Bashar al-Assad was losing his grip on power as the rebellion against him drags on.

Earlier on Monday, rumours had circulated that the ambassador to Rabat, Nabih Ismail, had also defected to the rebel side. A Syrian embassy official denied this but had no further comment.

Morocco’s Foreign Ministry did not immediately explain the timing or the reason for its decision to expel Ismail, but said in a statement the situation in Syria “cannot remain as it is”.

It added that Morocco wished for « an efficient and resolute action to ensure a political transition towards a democratic setup that guarantees Syria’s unity, stability and regional safety to achieve the brotherly Syrian people’s aspirations for dignity, freedom and development. »

Morocco recalled its own ambassador to Damascus in November 2011 and Monday’s decision was the latest in a series of diplomatic expulsions that has seen Damascus increasingly isolated as anti-Assad rebels gain strength.

In May, the United States, France, Britain, Canada, Germany, Italy, Spain, Australia, Bulgaria and Switzerland all kicked out Syrian diplomats in response to a massacre of 108 people in the town of Houla in May. Japan followed suit.

Morocco’s North African neighbours Tunisia and Libya, which saw their own leaders swept away in last year’s Arab Spring uprisings, expelled Syrian diplomats as far back as February.

Rights activists say more than 17,000 people have been killed in Syria since the uprising broke out in March 2011 against the autocratic regime of President Bashar al-Assad.

On June 6, participants at a Paris meeting of the so-called Friends of Syria which opposes the Assad regime decided to throw its support behind the opposition and hold their next gathering in Morocco.