U.S. stock index futures extended gains on Thursday after a stronger-than-expected June jobs report eased concerns about the health of the labor market despite uncertainties about U.S. trade policies.

The economy's expected to have added 110,000 jobs last month with the unemployment rate inching up to 4.3%, according to economists' mean estimate in a Dow Jones poll. That compares with May's 139,000 new jobs and 4.