The Women's Tennis Association has suspended play until May 2 as the coronavirus pandemic continued its unprecedented shutdown of world sport on Monday.
WTA said in a statement that tournaments in Stuttgart, Istanbul and Prague will "not be held as scheduled".
"We will make a decision in the week ahead regarding the remaining WTA European claycourt events and will continue to monitor this situation closely and its impact on the 2020 WTA Tour season," the WTA said.
The WTA had already canceled events through April 12, including the Volvo Car Open in Charleston, South Carolina, but tour organisers have now suspended play until May 2.
The Association of Tennis Professionals (ATP) suspended its tour for six weeks last Thursday due to the outbreak, while the International Tennis Federation also announced that it had suspended play until April 20 at the earliest.
Serena Williams will be spending the next six weeks in "solitude" as the tennis world goes on hiatus due to the pandemic, the 23-time Grand Slam champion said on Friday.