The Federal Reserve says it will buy a total of $105 billion worth of government bonds starting later this week as it launches a new program to invigorate the economy.

The bonds will be purchased through a series of 18 operations that start on Friday and end on Dec. 9. The purchases are the first since the Fed announced last week that it will buy a total of $600 billion worth of Treasury bonds over the next eight months.

The Fed will buy $75 billion of government debt as part of the new program. And, it will buy another $30 billion, using the proceeds from its vast mortgage portfolio.

That totals $105 billion for the first phase of the Fed’s government bond buying. The Fed last week said it anticipates buying on average $110 billion a month.