BEIJING, March 5 -- Following the announcement of the defense budget for 2015, a military strategist and national lawmaker said increased spending was needed to build a stronger army, but China's budget remained comparatively low.

China on Thursday set its 2015 defense budget at 886.9 billion yuan (about 144.2 billion U.S. dollars), a 10.1 percent rise year on year and its lowest increase in five years.

Chen Zhou, who is a research fellow at the Academy of Military Sciences affiliated with the People's Liberation Army (PLA) and a deputy to the National People's Congress, said China's defense spending was "appropriate and rational", and its share to gross domestic product (GDP) was lower than other major countries.

In terms of defense spending per head and its share to GDP, China spends less than other major countries, Chen said, adding that the United States' defense budget was more than 600 billion U.S. dollars.

This year is the fifth consecutive year that the defense budget has increased by double digits.

Chen, who led the compilation of China's defense white paper, said China was facing its most complicated domestic and international situations in history, according to the PLA Daily's Thursday edition.

"The missions of safeguarding the national integrity and sovereignty, the maritime and development interest are more arduous than ever before," Chen told PLA Daily.

Although an invasion is unlikely, regional wars and armed conflicts caused by external factors cannot be underestimated, Chen added, saying that military intervention would always be the last resort.

In addition, the army has taken on more international responsibility, another reason for a defense budget hike.

China's defense spending in 2014 accounted for 1.3 percent of its GDP, while defense spending of major countries account for about 2 percent to 5 percent of GDP.

In addition, China's defense spending is less than 6 percent of fiscal expenditure, while in other major countries the average number is 9.86 percent, Chen said.