LISBON - Portugal will tighten rules for the investor-oriented "golden visa" scheme following a scandal, but will not scrap it, Deputy Prime Minister Paulo Portas said Monday.

An investigation in November 2014 led to the detention of three high-ranking officials related to a golden visa scandal on suspicion of corruption, money-laundering and embezzlement.

Portas pointed out that the golden visa scheme has brought 1.27 billion euros ($1.44 billion) in investment and 100 million euros ($113 million) in taxation revenue.

"There are 13 other EU countries with similar investment programs, so I don't think it's clever to give up this program to the benefit of others."

Portas said the scheme would be extended to the science and culture sectors, and a foreigner can ask for a resident visa by investing 350,000 euros ($396,000) in these sectors.

Portugal launched the golden visa scheme in 2012 during the economic crisis to attract investment, giving wealthy foreign investors the chance to reside in the country and visa-free travel in the Schengen zone if they meet certain requirements by purchasing real estate worth half a million euros or investing 1 million euros in capital.