Top European Union leaders on Thursday welcomed the European Central Bank's surprise 750-billion-euro bond buying stimulus package and vowed they would do whatever it takes to protect the bloc's economy.

Brussels expects social and economic lock downs imposed to contain the global coronavirus epidemic to have a devastating effect on business, and leaders are scrambling to reassure the markets.

Late Wednesday, the ECB unveiled a Pandemic Emergency Purchase Programme, an emergency $820-billion scheme to pump cash into the economy by buying additional government and corporate bonds until a least the end of the year.

"Europe is pursuing a forceful economic response to the Corona Crisis," tweeted Charles Michel, the president of the European Council, which represents EU member state governments.

"No efforts will be spared to contain #COVID19 and shield our economies from further damage. I welcome the Emergency Purchase Programme (PEPP) from the ECB. #WhateverItTakes."

The speaker of the European Parliament, which is considering holding a virtual session by video conference to vote on emergency measures, also deployed the same motivational hashtag.

"The ECB is securing the European economy by protecting families, workers and businesses," tweeted David Sassoli, whose debt-plagued native Italy is one of the most exposed EU member countries.

Europe's stock markets rebounded on Thursday as investors digested the ECB move and its president Christine Lagarde's promise that there "are no limits to our commitment to the euro."