BEIJING — The Chinese authorities tightened their grip on Tuesday on the far western region of Xinjiang, where two clashes left dozens dead last week, by confiscating knives and offering rewards for information about possible separatist attacks, according to the state news media. The police also issued arrest warrants for 11 people said to be wanted for murder, bombings and other acts of violence.

The security drive, described by one senior official as a “people’s war,” has been accompanied by accusations in official media that shadowy extremist groups have orchestrated unrest among Uighurs, a Turkic ethnic group. One state-run newspaper sought to link an increase in violence in Xinjiang to Uighurs who were said to have trained in war-ravaged Syria.

On Monday, the newspaper — The Global Times, a populist tabloid owned by The People’s Daily, the main newspaper of the Chinese Communist Party — claimed that about 100 Uighurs had gone to Syria to join rebel forces there who are fighting the government of President Bashar al-Assad.

The newspaper quoted an unidentified Chinese security official as saying that the Uighurs went to Syria to “improve their fighting skills and gain experience in carrying out terror attacks.” Uighur exile groups and experts on the region have rejected government claims that the unrest in Xinjiang was the work of foreign-trained militants.