BANGKOK - Recent improvements in the global economy are "very fragile" and an escalation of the eurozone crisis remains the most immediate concern, IMF deputy managing director Naoyuki Shinohara said Tuesday.

While indicators had last year pointed to a big setback for the world there have in recent weeks been modest signs of improvement and stability in the key US and European economies, he said in a lecture at a university in Bangkok.

"Important policy actions carried out by European policy makers have helped and most recently the agreement on a new (debt) programme for Greece ... has also brought some relief," he said.

But, he said: "There is no room for complacency. A lot more needs to be done to give a fresh boost to growth."

Shinohara said in many countries public debt remained at all-time highs, limiting the scope for fiscal stimulus, and unemployment also remained very high.

"We are navigating a very narrow path before recovery of the economy and the risk of slippage is very high," he warned.

He said advanced economies "should press ahead with national and structural reforms to repair the damage done by the crisis" while emerging economies needed to remain vigilant for possible spillovers.

However the IMF expected "spillovers from the euro area to other regions will remain limited as long as the euro area is contained."

"Since the beginning of the year financial tensions in the euro area have eased, in large part thanks to the so-called long-term refinancing operation of the European Central Bank," he said.

In recent weeks the data has showed manufacturing activity for both advanced and emerging economies has improved, with readings above 50, which indicates growth, but Shinohara said a lot needed to be done to safeguard gains.

"Recent improvements are still very fragile. Important policy challenges remain to be addressed. Downside risks are still very large. The most immediate concern is still further escalation of the euro area crisis," he said.