GAZA, Nov 3 (Reuters) - A car exploded outside a police headquarters in the city of Gaza on Wednesday, killing one Palestinian, Hamas officials and witnesses said.

The Hamas Interior Ministry said the explosion was caused by an Israeli air strike but Israel Radio said it may have been the result of the premature detonation of a car bomb.

The explosion occurred during a period of relative calm between the Islamist-ruled Palestinian territory and Israel. A second Palestinian was wounded in the incident, Hamas said.

The assumption is that it was an Israeli targeting (attack), but our investigation continues in order to determine the exact causes, a spokesman for the Hamas Interior Ministry said.

A Hamas military medical official identified the dead man as 25-year-old Mohammed Jamal al-Nimim.

Witnesses said they saw a hole in the ground near the blast site, consistent with a missile strike.

The Israeli military, which has targeted Palestinian cars in air strikes in previous rounds of fighting, had no immediate comment on the incident. (Writing by Nidal al-Mughrabi; Editing by Andrew Dobbie)