South Korea's major mobile carriers SK Telecom, KT and LG Uplus will be banned from signing up new customers for offering excessive and illegal subsidies, the Korea Communications Commission (KCC) said in a statement Monday.

The companies were also fined a combined 11.89 billion won, KCC added.

The commission said that the firms violated the local Telecommunications Law after an investigation into illegal subsidies.

LG Uplus will be banned for 24 days, while SK Telecom and KT face business suspension for 22 days and 20 days, respectively.

The KCC fined SK Telecom 6.89 billion won; KT, 2.85 billion won; and LG Uplus, 2.15 billion won.

The KCC is currently caps subsidies at $249, in order to keep mobile operators from expanding their customer base at the cost of their profit margin.