"We have been dealing with the incident in accordance with the law," he told a news conference in Beijing on Monday.
"China is a country ruled by law. No country would allow this violence."
He said dozens of people were wounded in the violence in which "people were hacked and burned to death", but the Tibetan governor denied that lethal force had been used against protesters.
"Security forces used great restraint and did not carry or use weapons," the governor said.
A heavy security presence was maintained in Tibet throughout Monday.
Troops were also pouring into neighbouring provinces of Gansu and Sichuan to put down protests which have spread to Tibetan communities there.
The AFP news agency said that at least seven Tibetan protesters had been shot dead in Sichuan on Sunday during clashes with police.
China has also clamped down on the media, banning foreign reporters from Tibet and blocking access to YouTube, as well as many other overseas news websites.
In an unusual news conference at midnight on Monday the Chinese foreign ministry accused Tibetan activists of launching attacks on its embassies around the world and vowed to protect its territory.
Liu Jianchao, a ministry spokesman, said: "The Chinese government will unwaveringly protect national sovereignty and territorial integrity."
Liu did not single out any country, but in recent days clashes have been reported outside Chinese diplomatic posts in New York, Washington, Paris and Munich and other cities.
Meanwhile, Western countries offered limited criticism of China's crackdown, while Russia urged its ally to do whatever it could to "curtail unlawful actions".
Ban Ki-moon, the UN's secretary-general, said on Monday: "At this time I urge restraint on the part of the authorities and call on all concerned to avoid further confrontation and violence."
Condoleezza Rice, the US secretary of state, again called on China to exercise restraint and "engage the Dalai Lama".
The European Union also repeated its call for "restraint on all sides".
Over the weekend large deployments of troops had been used to quell the Lhasa protests, which began on the anniversary of a 1959 uprising against Chinese rule of the region.
Following reports of deaths the Dalai Lama, Tibet's spiritual leader in exile, called for an international inquiry into what he said was China's "rule of terror" and "cultural genocide" in Tibet.
The uprising comes less than 200 days before the opening ceremony for the Olympic Games takes place in Beijing.
Jacques Rogge, the International Olympic Committee (IOC) chief, has said he is concerned about the Chinese crackdown in Tibet and the neighbouring provinces but rejected the idea of a boycott.
1950 China invades Tibet
1959 Dalai Lama flees to exile in India after failed uprising against Chinese rule
1960s-70s Hundreds of monasteries destroyed during Chinese Cultural Revolution
1965 China announces creation of Tibet Autonomous Region
1989 Dalai Lama awarded Nobel Peace Prize for leading non-violent struggle for Tibet
2006 Opening of first rail line linking Tibet to rest of China
EU nations and Olympic committees have also opposed a boycott, arguing that sports and politics should not be linked.
Patrick Hickey, head of the European Olympic Committees, told the Associated Press news agency: "Under no circumstance will we support the boycott. We are 100 per cent unanimous.
"Not one government leader has called for a boycott. A boycott is only a punishment of the athletes."
However, the Swiss Olympic committee, which also ruled out a boycott, urged the IOC to break its silence over Tibet.
Joerg Schild, the president of the Swiss Olympic committee, said on Sunday: "The IOC must remind China of the expectations that were linked to granting it the games."
The Chinese organisers of the Olympics have said the Tibetan unrest will not have an impact on the games.
Sun Weide, a spokesman for the Beijing Organising Committee of the Olympic Games (BOCOG), said preparations for the torch relay across Mount Everest and Tibet "have been proceeding very smoothly and according to schedule".