The Federal Reserve on Friday launched a wave of $37 billion of Treasury security purchases under the enhanced market liquidity measures it announced on Thursday to address volatile conditions in the government bond market caused by the coronavirus outbreak.

The Federal Reserve Bank of New York, the market agent for the Fed system, said purchases began at 10:30 a.m. EDT and would continue into the afternoon as it targeted five different maturity sectors.

The purchases account for roughly half of $80 billion in planned monthly purchases that the Fed revised this week to include a wider range of maturities. That was a notable shift from the central bank's previous approach, which focused on short-term Treasury bills and was described as a "technical" program aimed at boosting the level of reserves in the banking system.

The accelerated purchases are "intended to address highly unusual disruptions in the market for Treasury securities associated with the coronavirus outbreak," the New York Fed said Friday.

The markets desk will adjust future purchases "as needed to foster smooth Treasury market functioning" and plans to post a revised schedule, the bank said.

Meanwhile, the coronavirus could realistically infect a quarter of the U.S. population and put "significant stress" on the medical system if it is not put in check, Boston Federal Reserve President Eric Rosengren said on Friday, calling for companies to take "disruptive" steps like limiting travel and meetings to halt the outbreak.

"If one-quarter or more of the population ultimately acquires the virus, as seems well within the realm of possibility, the numbers therefore suggest that we will still face a very significant challenge," Rosengren said in a joint statement with Dr. Paul Biddinger, the director of the Massachusetts General Hospital Center for Disaster Medicine.

"The tactics that can dent a pandemic are, to be sure, somewhat disruptive. And inconvenient. But they are the right thing to do. And the time is now."

The remarks represented an unusual break from the norm, indicating the urgency of the situation. Central bankers are typically reluctant to make recommendations about issues outside monetary policy, and are technically in a "blackout" period ahead of next week's Fed policy meeting that limits their commentary on interest rates and other direct policy matters.

But, in the case of the coronavirus outbreak, the U.S. central bank is struggling to both see the scope of the problem, and manage a crisis that has developed with such real-time speed that it has seen the Fed cut interest rates and roll out emergency liquidity tools to buttress shaky markets.

Lacking firm data on how the virus might spread and impact the economy, Fed officials have turned to their own sources of information about what to expect, in Rosengren's case tapping the massive healthcare industry around Boston.

The statement with Biddinger carried both a sense of urgency and a critique of businesses elsewhere that "waited too long to take action, waiting for other companies' actions or delayed responses from government organizations."

"We’re talking about things like canceling events that involve gatherings ... instituting work-from-home approaches for all who can ... and doing what we can to tide over workers and businesses for whom demand may dry up for a while," they said.

"These steps may be difficult, and take some adjustment. But they might, over the coming days and weeks, mitigate the spread of the virus, and its economic impact. And that is well worth it. The inconveniences could forestall much worse options."

Meanwhile, Trump in a tweet Friday continued to press a payroll tax cut, which has received a cool response from both fellow Republicans in Congress as well as Democrats.

Any measure must pass both the Democrat-controlled U.S. House of Representatives and the Republican-controlled Senate before Trump could sign it into law.

Trump also took the opportunity to slam the Federal Reserve again, tweeting:

"The Federal Reserve must FINALLY lower the Fed Rate to something comparable to their competitor Central Banks. Jay Powell and group are putting us at a decided economic & physiological disadvantage. Should never have been this way. Also, STIMULATE!"