Jakarta, Feb. 18 -- Indonesian authorities have seized about 13 kilograms of crystal methamphetamine and arrested two Iranian nationals in a coordinated drug raid in Jakarta, officials said Wednesday, following several days of surveillance on an international shipment.

The case was uncovered after three days of monitoring cross-border goods and gathering intelligence from Feb. 13 to 15, said R. Syarif Hidayat, director of narcotics interdiction at the Directorate General of Customs and Excise.

In a statement, Hidayat said the investigation began when customs officers detected a suspicious leather chest shipped from Iran using an X-ray scanner at a post office in Pasar Baru, Central Jakarta, on Feb. 12.

Authorities discovered 11.56 kilo...