GAZA - The Israeli army has besieged the Al-Shifa hospital in Gaza amid heavy clashes with the Palestinian militants in the territory, Palestinian security sources said Saturday.

"Tanks and military vehicles of the Israeli army have been encircling the vicinity of the Shifa hospital from all main axes for hours, coinciding with heavy artillery shelling in the area," Palestinian security sources told Xinhua.

They said that ambulances were unable to leave the Al-Shifa Complex and transfer the wounded amid fears that they might become a moving target.

Local eyewitnesses said that they heard massive explosions during the night from violent armed clashes between Israeli army forces and militants of the Al-Qassam Brigades, the armed wing of the Hamas movement, in several areas of Gaza City, especially in the vicinity of the Shifa Hospital.

Established in 1946, the Al-Shifa Complex is the largest health institution in the Gaza Strip. It includes three specialized hospitals and employs 25 percent of hospital workers across the strip.