The European Union’s executive arm will give final warnings to Sweden and France on Wednesday before taking them to the European Court of Justice, the sources said.
Meanwhile, Greece will get a first warning from the European Commission, the sources also said, speaking on condition of anonymity.
The Commission also has cases underway against Austria, Denmark, Finland, Germany, Hungary, Italy and the Netherlands.
Although the European Commission is not seeking to liberalise the sports gambling market, it has recently been leading an offensive against state monopolies in the sector, which it says keep out newcomers.