The warnings urge Chinese nationals and Chinese-funded institutions in the US to be cautious

China on Tuesday issued a pair of travel alerts to its citizens going to the United States, warning them about police harassment and crime.

The warnings come amid an escalating trade war between the world's two largest economies and other tensions, including trading barbs over each others' human rights records.

"Recently, shootings, robberies and thefts have occurred frequently in the United States," state media reported, citing a statement from the Ministry of Culture and Tourism.

The statement urged Chinese tourists to "fully assess the risk" and "improve their awareness of safety and security".

In a separate warning, China's foreign ministry said US law enforcement agencies have "repeatedly" used methods such as immigration and on-site interviews to "harass" Chinese citizens in the US.

It urged Chinese nationals and Chinese-funded institutions in the US to be cautious and "increase awareness and strengthen preventive measures."

The warnings come a day after the education ministry said students and academics were facing US visa problems and urged them to assess the "risk" of travelling to the United States.