The United States and Israel are watching with concern the growing military cooperation among Turkey, China and Iran, especially following a joint Turkish-Chinese air-force exercise last week.

Open gallery view Chinese J-11 fighter jet

Until two years ago Israel was Turkey's main partner for air combat training.

In 2001 the Turkish air force inaugurated a tactical air warfare center in Konya with Israel and the United States.

Until 2008 the Israel Air Force was a frequent guest in Turkey's sky and a regular participant in the country's big annual exercise, Anatolian Eagle.

In the wake of Operation Cast Lead and the subsequent deterioration of bilateral relations Turkey last year revoked Israel's participation in the maneuvers. The United States decided not to take part in the exercise this year because of that decision. A number of other NATO members followed suit.

Turkey replaced the Israel Air Force with its Chinese counterpart. China sent Sukhoi SU-27 fighter aircraft and pilots to train with Turkey's F-16 fighters. In the past these exercises were held in relatively openness, but last week they were held covertly, with only a brief report appearing in the Turkish media after the exercise.

The West has been watching the changes in the Chinese army's structure, and especially the long-range naval and aerial exercises that indicate Beijing's intention to acquire the ability to conduct warfare far from China's borders.

The Chinese are also aggressively pursuing cyber warfare capabilities, employing some 60,000 hackers at it, according to foreign intelligence reports.

The Obama administration protested Turkey's military cooperation with Iran after it was reported that the Chinese fighter planes were sent to Turkey via Pakistan and Iran.

The developing ties among Turkey, Iran and China are also reflected in weapons deals, with Iran buying from China mainly missile technology.

The C-802 antiship missile fired by Hezbollah in the Second Lebanon War at the Israel Navy's Hanit missile boat was manufactured in Iran with Chinese technology.

China has also developed a surface-to-surface rocket-launching system together with Turkey. China's Prime Minister Wen Jiabao is due to visit Ankara this month and to sign several bilateral cooperation agreements.

Turkey and China are also involved in projects to build oil pipelines from Iran.

Another reason for the close relations between the two states is that China, as a permanent member of the United Nations Security Council, has been in the forefront of opposition to imposing harsher sanctions on Iran in connection to the Islamic state's nuclear program.