WASHINGTON (AP) — President Donald Trump said on social media Thursday that he is directing the federal government to buy $200 billion in mortgage bonds, a move he said would help reduce mortgage rates at a time when Americans are worried about home prices.

Trump and the White House have been trying to show they are responding to voter concerns about affordability ahead of midterm elections in November. Home prices have generally risen faster than incomes because of a persistent construction shortfall, making it harder for renters to buy their first home and for existing owners to upgrade to a new property — a challenge that dates back to Trump’s first term and the recovery from the housing market collapse that triggered the global financial crisis in 2008.

Trump said the two mortgage companies under government conservatorship, Fannie Mae and Freddie Mac, have $200 billion in cash that will be used to make the purchase.

“This will drive Mortgage Rates DOWN, monthly payments DOWN, and make the cost of owning a home more affordable,” Trump posted on social media.

White House officials did not immediately respond to questions about the timelines for how purchases would occur.