karzai and zhou
Chinese domestic security chief Zhou Yongkang and Afghan President Hamid Karzai (Reuters).

China and Afghanistan have signed a series of economic and security agreements following a surprise visit by Chinese domestic security chief Zhou Yongkang to Kabul, Reuters reported.

The visit, the first by a Chinese official in 46 years, was not announced in Beijing due to security reasons.

Zhou and Afghan President Hamid Karzai held discussions on issues such as terrorism, drug trafficking and transnational crimes along with matters concerning bilateral trade and investment.

Zhou said China was ready to help in bringing peace and stability to militancy-ravaged Afghanistan.

The BBC reports that, under one of the agreements, China will assist in the training of Afghan police. Around 300 Afghan policemen will be trained in China in the next four years.

"It is a priority of China's foreign policy to strengthen good-neighboured relations with surrounding countries. It is the consistent policy of the Chinese government and the CPC to consolidate and develop China-Afghanistan relations," Zhou said in a statement published by the state-owned news agency Xinhua.

"We will continue to provide assistance to Afghanistan with no attached conditions and sincerely hope the Afghan people can regain peace as soon as possible and build a better home in a peaceful environment," he added.

Analysts suggest that the Chinese visit gains significance as US and Nato troops are to pull out of Afghanistan and several other nations are looking to boost their influence in the country.

China is one of the first countries to have invested in Afghanistan, said Xinhua, adding that Chinese direct investment in the country stood at $200m at the end of 2011.

China's Afghan investments include mineral resources, copper mines and the extraction and exploration of oil.

"Zhou's visit shows China is seriously planning its Afghan strategy for the days after 2014," Wang Lian, a professor with the School of International Studies at the Peking University in Beijing, told Bloomberg.

"Almost every great power in history, when they were rising, was deeply involved in Afghanistan, and China will not be an exception."