Li Keqiang, China's prime minister, has set off for a four-country tour of Africa, acknowledging "growing pains" in China-Africa cooperation.

In a news release quoted by the state news agency on Sunday, Li urged Chinese companies to strictly abide by local laws and regulations, hold themselves accountable for the quality of their projects and goods and to consumers, and "shoulder due responsibility" for local communities and the environment.

Last year, China-Africa trade reached $210bn, with more than 2,500 Chinese companies operating on the continent, according to Xinhua.

But tensions exist around allegations of shoddy construction and a lack of respect for employment and other local laws.

Many projects in Africa funded by China have Chinese men working on them, an issue that has prompted complaints from locals who fret that jobs that they should be doing are going to Chinese.

The quality of Chinese products sold in most African countries has also led to complaints that they are substandard.

Li said companies have encountered "growing pains" and the Chinese government takes such issues seriously.

He said that problems in the China-Africa relationship were, however, "isolated cases".

Troubles in Zambia 

Last year, Zambia's government seized control of a Chinese-run coal mine, saying Chinese managers had failed to address safety, health and environmental concerns.

In 2010, two Chinese managers at the mine were accused of shooting miners during a labour dispute, and clashes in August reportedly saw one Chinese worker killed and two others injured.

Li is visiting Ethiopia, where the Chinese funded the construction of the headquarters of the African Union, and Nigeria, which overtook South Africa this year as Africa's largest economy.

He will also visit Angola, a major oil producer, and Kenya.

The visit to Africa, his first since he became prime minister last year, is the second in more than a year by China's top leaders.

In March 2013, Chinese President Xi Jinping signed a string of deals during a visit to the Republic of Congo.

The deals included a river port in Oyo, Congolese President Denis Sassou Nguesso's hometown, and a sea port in Pointe-Noire that can export mineral ores shipments.

Before Congo, Xi visited Tanzania and South Africa.

China has become one of Africa's major trading partners in recent years, but has been criticised by the West for ignoring human rights abuses in some of the countries it deals with.

Source: Al Jazeera and agencies