Moe Kyaw Than, 45, a volunteer with Burma's Red Cross Society, reacts after being wounded in clashes between the Burmese army and rebel forces in February. (Reuters)

BEIJING -- For days, the anger has grown online.

After a bomb from a Burmese aircraft killed four Chinese near the China-Burma border, many Chinese have been expressing their outrage on the Internet -- not only against the Burmese government but against their own for not taking a harder stance.

So far, Chinese leaders have complained to Burma, also known as Myanmar, about the bombing, which occurred on Chinese soil, and sent a few jets on a symbolic patrol of the border, but they haven't gone much further. And while Chinese leaders have often eagerly fanned the flames of nationalistic anger in the past, they have tried hard to tamp down such sentiments in this case -- going as far as censoring online posts about the incident and paying off the victims' families.

The surprising restraint highlights the delicate nature of China's relationship these days with Burma. China has been trying to preserve and rebuild its ties with Burma in recent years amid that country's transition from an authoritarian, military-run government and its surprising overtures to the West.

[Here’s why students in Burma are taking to the streets]

Burma remains a large importer of Chinese weapons. Many of its biggest projects are Chinese-backed or owned -- an arrangement that allows China to secure energy and raw materials that are crucial to sustaining its ever-expanding economy.

But those diplomatic and strategic niceties have not blunted popular opinion in China as news of Friday's bombing has spread.

The bomb fell in a border village of China's Yunnan province, near where the Burmese government has been fighting rebels in its Kokang region. Burma has blamed the bombing on rebel forces. But China says the bomb was clearly dropped by a Burmese air force plane.

Comments in Chinese social media have ranged from sarcastic to mocking to outright demanding.

"Is this because the Chinese people are so cheap and can only die for nothing?" "All Chinese military is good for is drinking Maotai [a kind of luxury wine used to bribe corrupt officials]?" “Imagine how this would have played out if the bombing happened to the U.S.?”

As of Tuesday, many online comments had already been censored. China's local government has also paid each victim's family $3,200 as compensation.

Even China's most nationalistic paper, the Global Times -- which is published by China's official People's Daily -- has tried to ease public anger. On Monday, an opinion piece argued, "Your brain must be injected with water if you think Myanmar's military is dropping bombs on purpose."

China, it argued, is not like the United States and will not go around killing people for little reason.