Microsoft's LinkedIn said Monday it would lay off 668 employees across its engineering, talent and finance teams in the second round of job cuts this year for the social media network for professionals as demand for hiring services slows.

The cuts, which affect more than 3% of the 20,000-strong staff, add to the tens of thousands of job losses this year in the technology sector amid an uncertain economic outlook.

The sector has laid off 141,516 employees in the first half of the year compared with about 6,000 a year ago, according to employment firm Challenger, Gray & Christmas.

LinkedIn makes money through ad sales and by charging for subscriptions to recruiting and sales professionals who use the network to find suitable job candidates.

The social media network had in May decided to cut 716 jobs across sales, operations and support teams to streamline its operations and remove layers to help make quicker decisions.