Taiwanese smartphone maker HTC Corp (TPE:2498) laid off about 20 percent of the workforce at its U.S. offices on Friday, sending its shares down more than 3.5 percent on Monday.

The struggling phone maker, in a statement, cited by Reuters, said that the move was to “to streamline and optimize our organization and improve efficiencies after several years of aggressive growth.” 

The company did not reveal how many jobs were cut, but according to sources familiar with the matter, the downsizing affected about 30 jobs from multiple departments, The Verge reported. 

“This is a hard decision that has direct impact on people who have contributed to the growth HTC has experienced the past several years,” HTC said in its statement, All Things D reported. “However, to achieve our long-term goals as a business and return maximum value to our shareholders, this is a necessary step to drive ongoing innovation.”

HTC, which has a total workforce of about 17,000 employees worldwide, had nearly 150 employees and contractors in its U.S. division before the layoffs. HTC also had witnessed some high profile exits from the company, which included the departure of its chief product officer, Kouji Kodera, and communications chief, Jason Gordon, among others, in May.

HTC, in its statement, said it will continue “to hire in strategic areas and encourage impacted employees to apply for open positions that are a fit for their skills.”

The company, which had posted strong growth earlier witnessed a sharp decline in smart phone sales in recent quarters. The company’s sales have fallen more than 31 percent so far this year, compared to the same period in the previous year, Reuters reported. HTC's monthly revenue in August fell 45 percent from the same period in 2012 while revenues fell by about 16 percent from July 2013, according to the company website.

However, HTC has been attempting a comeback, which includes a publicity campaign featuring Robert Downey Jr., to raise its profile in the U.S., which is its biggest market, following the encouraging performance of its flagship smartphone, HTC One.