Premier Li Keqiang urged police across China to strengthen public security measures at all levels.

As the death toll from Saturday's terrorist attack at Kunming Railway Station in Yunnan province rose to 29 and the number of injured topped 130, the search for the perpetrators continued.

On Sunday, Kunming's government said evidence at the scene indicated that the attack was committed by terrorists from the Xinjiang Uygur autonomous region. If so, it would be the latest in a string of attacks related to the autonomous region, including incidents in January and February.

More than 10 masked people, dressed in identical black outfits and wielding large knives, stabbed and slashed passengers in the station's square and ticket hall. The attack began at 9:20 pm on Saturday and lasted about 12 minutes, according to China Central Television.

Police killed four of the assailants at the scene. Their identities have yet to be established. One woman was arrested.

There was a heavy police presence at the station on Sunday. The bloodstains had been washed away and passengers had returned to the busy transport hub. Flowers had been laid at the base of a bronze sculpture in the center of the square. Police had placed unclaimed luggage in a corner of the station, but some of the owners will never reclaim their belongings.

On Sunday, Lyu Xinhua, spokesman for the Second Session of the 12th National Committee of the Chinese People's Political Consultative Conference, told a media briefing that the attack exposed the "anti-human and anti-social" nature of the perpetrators and said they will be severely punished.

Ban Ki-moon, the UN secretary-general, strongly condemned the attack. In a statement released on Sunday, he said there was no justification for the slaughter of innocent civilians and hoped that those responsible will be brought to justice.

The UN Security Council also issued a statement to condemn the attack "in the strongest terms". Members of the council "reaffirmed that terrorism in all its forms and manifestations constitutes one of the most serious threats to international peace and security, and that any acts of terrorism are criminal and unjustifiable regardless of their motivation, wherever and whenever and by whomsoever committed".

The United States was shocked and condemned by the brutal violence that caused heavy casualties, said the US State Department and the US Embassy in Beijing.

The Chinese community in the US was in shock hearing the news.

Chen Xianzhong, chairman of the New York Alliance for Defending the Diaoyu Islands, said that the violence is "simply terrifying".

"It is unforgivable to do such a thing to innocent people, regardless of the reasons behind it, especially when there are so many older people and children," he said. "At first I thought it was an outburst, but hearing that it was planned, I feel angry about it. It shouldn't have happened."

Through the Chinese Foreign Ministry and the Chinese Embassy in Washington, the US government extended its condolences to the deceased and voiced sympathy for the victims and their families.

The French Foreign Ministry said in a statement that France strongly condemns the bloody attack and said nothing can justify such acts.

It also extended its condolences to the victims' families and expressed solidarity with the government and the Chinese people.

The Russian President Vladimir Putin also condemned the attack.