JERUSALEM (JTA) — The Israel Defense Forces cut down the fishing zone for fishermen off the coast of the Gaza Strip after balloons carrying explosives sent from Gaza sparked several fires in southern Israel.

Some 11 fires were started in Gaza-border communities on Wednesday, according to Israel’s Fire and Rescue Services. At least six were sparked by so-called incendiary balloons. There have been several such fires in recent days.

The decision on Wednesday night to restrict the Gaza fishing zone to 10 nautical miles, came a day after the zone had been increased to 15 nautical miles. The zone has been as small as six nautical miles, and before the second intifada began in 2000 it was as large as 28 nautical miles.

The allowed fishing zone was reduced to six nautical miles in April after Islamic Jihad fired a missile on Israel.

The range of 28 nautical miles had not been an option to the fishermen of Gaza since second intifada, which launched in 2000.

The increase reportedly was in order to honor an unofficial ceasefire agreement between Israel and Hamas, which controls Gaza. But the balloons carrying fire bombs could be a violation of that deal. Israel has denied that there is such a cease-fire in place.

All of the fires were under control by late Wednesday night.

An extreme heat wave has blanketed Israel for several days. Temperatures on Wednesday hovered in the high 90s and are forecast to climb as high as 110 to 115 Fahrenheit by Friday throughout most of the Jewish state. The hot and dry weather has led to fears of widespread fires.

The weather led to the curtailment Wednesday night of traditional Lag b’Omer bonfires.