Fifor made the announcement on Monday, after the Romanian Senate's defense committee debated a draft law on the purchase of the missiles and then voted for the acquisition of the systems worth 3.9 billion dollars.
He said the bill would reach the Senate on November 21 to get final approval and that the missiles would become operational by 2020.
The purchase is part of Bucharest’s long-term military cooperation with Washington. Romania is one of the United States' staunchest allies in Eastern Europe along with Poland.
Romania has been part of NATO since 2004, and plans to increase its military spending to two percent of its gross domestic product by the end of this year.
Romanian President Klaus Iohannis has previously stressed that the purchase of US-built Patriot missile systems is aimed at bolstering the country’s defense and not antagonizing Russia.
Moscow has on several occasions criticized Washington for deploying ballistic missile systems in Romania, saying the deployment would violate the Intermediate-Range Nuclear Forces (INF) treaty signed between the US and the Soviet Union in 1987.
The United States has deployed contingents of troops in Eastern Europe and the Balkans since the reunification of the Back Sea peninsula of Crimea with Russia following a referendum in March 2014. The US deployments have been supplemented by four NATO battle groups of more than 1,000 soldiers.
Western countries have moved to step up their military presence in Eastern Europe to deter what they call the Russian “aggression.”
Moscow is wary of NATO’s military build-up near its borders. In response, Russia has beefed up its southwestern military capacity, deploying nuclear-capable missiles to its Baltic enclave of Kaliningrad bordering Poland and Lithuania.