All ATP tournaments in July have been suspended, including the Hamburg Open - a third-tier 500 level event.
WTA events in Bastad, Bucharest, Lausanne and Jurmala have been called off, with similar events in Palermo and Karlsruhe set to follow.
The US Open, which takes place in New York at the end of August, remains penciled in for that date.
No professional tournaments have been played since the start of March, with the French Open and Wimbledon among the events called off.
"Just like tennis fans, players and tournament hosts all over the world, we share in the disappointment the tour continues to be affected in this way," said ATP chairman Andrea Gaudenzi.
"We continue to assess all of our options in an effort to resume the tour as soon as it is safe to do so, including the feasibility of rescheduling events later in the season."
Wimbledon, which was due to start on 29 June, was cancelled for the first time since World War Two.
French Open organizers announced their intention to play the clay-court Grand Slam, which should have started on 24 May, in late September and early October instead.
In theory, it would take place after the North American hard-court season, which culminates with the US Open at Flushing Meadows.
The hard-court events in the United States and Canada remain in place for now. The latest suspension is likely to run up to the WTA event in San Jose and the ATP event in Washington on 3 August, with a further decision set to be made next month.
These tournaments are followed by the Rogers Cup - which is split across Montreal and Toronto - and the Cincinnati Open, events which are both categorized among the biggest outside of Grand Slams.