Chinese air defense forces on Thursday battled rain while continuing a five-day military exercise featuring drills that include the relocation of air defense positions and command posts.

More than 12,000 Chinese military personnel, along with seven types of military aircraft, divided into Red and Blue rivals, took part in the exercise-- code-named "Vanguard-2010,"-- which started on Tuesday in seven cities across Henan and Shandong Provinces.

At about 6 a.m. Thursday, the Red forces started their seven-hour relocation drill, which was complicated by heavy rainfalls that began early Thursday morning in Shandong and Henan Provinces.

By 1 p.m., the Red forces had finished relocating to their new defense positions, while the Blue forces launched a second round of attacks which began on Wednesday.

Earlier reports said the annual drill, consisting of two phases to run from Tuesday to Saturday, would feature emergency evacuations, war planning, reconnaissance, early warning activities, ground-to-air attacks and evacuations of command posts during its first phase which ends on Thursday.

Its second phase will include testing Chinese air defense troops' abilities in fighting air units in a "complicated electromagnetic environment."

A "Vanguard-2009A" exercise was held in 2009 involving 5,000 soldiers and officers from the Chinese army and air force and more than 50 types of military equipment.

In 2008, "Vanguard-2008" included participation by a 2,200-strong armored brigade from the People's Liberation Army (PLA) Jinan Military Area Command. The exercise was partly opened to foreign students studying at China's military academies.