TEHERAN - The death toll from a massive explosion at a port in Iran's southern province of Hormozgan on Saturday has risen to 46, the official IRNA news agency reported Monday.

The explosion and the subsequent fire left more than 1,200 people wounded, of whom 138 were hospitalized, IRNA quoted Mehrdad Hassanzadeh, director general of the provincial crisis management organization, as saying.

ALSO READ: At least 25 killed, 800 wounded in Iran's port explosion

The cause of the incident has not been determined yet, according to IRNA.

In remarks to the semi-official Tasnim news agency on Monday, Hossein Zafari, spokesperson for Iran's National Disaster Management Organization (NDMO), said the fire at the port will be completely extinguished soon.

On Sunday, the Iranian government declared Monday a day of national mourning. Meanwhile, Iranian President Masoud Pezeshkian visited the port to assess the circumstances of the blast, and visited some of the injured.

READ MORE: Israeli forces carry out airstrike on Beirut's southern suburbs

Hossein Sajedinia, head of the NDMO, told Iran's IRIB news agency on Sunday that some containers at the port contained flammable materials, such as pitch, and some others had chemicals in them.

Despite the incident, the port's wharfs have resumed operations and cargo handling, according to IRNA.