MANILA- The Armed Forces of the Philippines (AFP) has acquired from the United States a fresh supply of munitions such as rockets and bombs to replenish its arsenal depleted by ongoing offensives against Islamic State-linked extremists in Marawi City.

"Before Marawi happened, we have [a] stockpile of rockets and bombs but we depleted it, we exhausted them in Marawi," Defense Secretary Delfin Lorenzana said.

"So it's just normal for us to stockpile again for other purposes. This is not only for Marawi. The Marawi (crisis) is almost over. We may not even use some of them in Marawi," he added.

Lorenzana, however, did not disclose the quantity of rockets and bombs acquired from the US, as well as the amount involved.

A C-130 transport plane from the Philippine Air Force flew to Arizona on June 23 to pick up the supplies. The aircraft returned to Manila on Saturday.

Various Air Force planes, including the just acquired FA-50 fighter jets from South Korea, are supporting the operations in Marawi City, delivering rockets and bombs.

Clashes between government troops and Maute terrorists broke out in Marawi City on May 23, prompting President Rodrigo Duterte to declare martial law in the whole island of Mindanao.

Thousands have fled the city while more than 461 people have been killed in ongoing clashes, among them 337 terrorists, 85 government forces, and 39 civilians.

The US and Australia have been providing technical support to the Philippine military to boost intelligence gathering amid its offensives.