The European Central Bank (ECB) again increased emergency liquidity funds for Greece's banks Monday, according to a Greek bank source who said the ECB may renew the hike "at any time" if necessary.

The new increase of the ECB's Emergency Liquidity Assistance was the third since Wednesday and came as Greek savers continued withdrawing their money in large volumes from the country's banks.

Though the total amount of the new reserve was not divulged, the Greek source said ECB "governors may meet at any time ... including today or tomorrow" to review the situation, which is likely to evolve against an emergency eurozone summit in Brussels later Monday to seek an accord on Greece's debt crisis.