The government has stepped up already tight controls over the internet since President Xi Jinping took power five years ago, in what critics say is an effort to restrict freedom of speech and prevent criticism of the ruling Communist Party.
The government says all countries regulate the internet, and its rules are aimed at ensuring national security and social stability and preventing the spread of pornography and violent content.
A report to the on-going session of the standing committee of China's largely rubber stamp parliament said the authorities had targeted pornography and violence in their sweeps of websites, blogs and social media accounts, Xinhua said.
As well as the 13,000 websites shut down, almost 10 million accounts had also been closed by websites, it added. It did not give details but the accounts were likely on social media platforms.
"Internet security concerns the party's long-term hold on power, the country's long-term peace and stability, socio-economic development and the people's personal interests," Xinhua said.
More than 90 percent of people surveyed supported government efforts to manage the internet, with 63.5 percent of them believing that in recent years there has been an obvious reduction in harmful online content, it added.
Authorities including the Cyberspace Administration of China have called more than 2,200 websites operators for talks during the same period, he said.
In addition, operators have closed nearly 10 million internet accounts for violating service protocol, while information on terrorism and pornography has been removed.
China ushered in a tough cyber security law in June, following years of fierce debate around the controversial legislation that many foreign business groups fear will hit their ability to operate in the country.
China maintains a strict censorship regime, banning access to many foreign news outlets, search engines and social media including Google and Facebook.
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)