"The security of Bahrain and Saudi Arabia is indivisible - being two bodies with one soul," Gulf Daily News quoted the Saudi king as saying on Tuesday.
He rejected any foreign interference in Bahrain's internal affairs and expressed unwavering support for the Persian Gulf state's independence and sovereignty, saying that the security of the two countries is intertwined.
Saudi Arabia has deployed its troops to Bahrain since over a month ago to help the sheikhdom quell anti-regime protests there. Bahraini troops backed by Saudi forces, have stepped up their suppression of protesters as rallies continue across the country.
In March, Saudi Arabia, the United Arab Emirates and Kuwait deployed their troops in Bahrain to reinforce the brutal armed clampdown on mass protests.
Scores of protesters have been killed and many others gone missing during the harsh crackdown.
The Human Rights Watch reports that more than 600 opposition activists and protesters have been arrested in the recent weeks.
Anti-Saudi sentiment is growing in Bahrain, where people have been demanding an end to more than 40 years of al-Khalifa rule in the Persian Gulf state.