Friends of an experienced Algerian diver who went missing 32 kilometers (20 miles) off Dubai have raised $55,000 to assist rescue teams in their search after he disappeared while spearfishing.

Adel Ait-Ghezala, a doctoral student at the American University in Washington, went missing Wednesday afternoon after he went free diving with friends in the Persian Gulf.

Family friend Abdullah Al-Arian said Monday that the money was raised in two days through a crowd-funding website. Friends say the donations will be used for volunteers to charter boats and helicopters for a more expansive search.

Ait-Ghezala's brother Ahmed says Dubai rescue teams are searching the waters and "doing their utmost to find Adel."

Friends and family say they still trying to figure out why Ait-Ghezala failed to surface from the dive.