Cybersecurity firm FireEye, well-known for investigating major data breaches and state-sponsored hacking groups, is set to slash up to 400 of its 3,400 jobs after "lower than expected" growth blamed on a decrease in activity from Chinese adversaries.

"As we continue to fight the battle against cyberattacks, we have seen that the size and scope of the threat landscape have changed," FireEye said in a statement sent to IBTimes UK via email.

"The whole remediation process used to be more complex, however we are now seeing that the duration and size of each incident response engagement is reducing due to the nature of attack," it continued. "As a result, services growth at FireEye was lower than expected and this lessened new subscription and product pull-through."

Based on the firm's financials, FireEye has cut its full-year revenue forecast to $716m-$728m from $780m-$810m.

For the second quarter of 2016, it reported revenue of $175m, missing its previous projection of $178m to $185m. The cybersecurity firm posted second quarter billings of $196.4m, below its forecast of $200m-$215m.

In June, FireEye was among a number of cybersecurity firms that insisted cyber espionage attacks from China appeared to be on a drastic decline. This, experts asserted, was an indication that Beijing made good on its promises to cut back on hacking and cyber-intrusions that it made with US President Barack Obama in 2015.

However, while state-sponsored hackers had dropped its traditional routines, cybersecurity experts said it had increased spying on targets in other countries – namely Russia, the Middle East, and Japan. At the time, US assistant attorney General John Carlin noted: "It seems like there has been a change in activity. There is a debate as to how long lasting it might be, but there has been a change."

Kevin Mandia, chief executive of FireEye explained the planned changes and staff cut-backs to Reuters, where he claimed the firm is now dealing with more cybercrimes with a financial motive that are easier to combat. "The size and scope have changed," he said.

FireEye said that it now plans to introduce updated versions of its products and "improve sales execution" to help bolster its financial performance. It told IBTimes UK: "We still have much work to do, but FireEye has the critical assets necessary for long term success, and that we are taking these additional steps to achieve balanced growth and profitability."