A financial stability watchdog in the European Union has warned eight countries about risks in their residential real estate markets, including rising levels of mortgage debt or overheated house prices.

The European Systemic Risk Board issued the warnings to Austria, Belgium, Denmark, Finland, Luxembourg, the Netherlands, Sweden and the United Kingdom.

It said in a statement Monday that the "key vulnerabilities" relate to rising indebtedness among households, which could impact on their ability to pay down their mortgage or to "the valuation or price dynamics of residential real estate."

However, it said it found no short-term troubles looming and that its caution related to the medium term, or a somewhat longer horizon.

The board is charged with identifying risks to the financial system as a whole.