Five lines of ancient script on a shard of pottery could be the oldest example of Hebrew writing ever discovered, an archaeologist in Israel says.

The shard was found by a teenage volunteer during a dig about 20km (12 miles) south-west of Jerusalem.

Experts at Hebrew University said dating showed it was written 3,000 years ago - about 1,000 years earlier than the Dead Sea Scrolls.

Other scientists cautioned that further study was needed to understand it.

Preliminary investigations since the shard was found in July have deciphered some words, including judge, slave and king.

The characters are written in proto-Canaanite, a precursor of the Hebrew alphabet.