"It is a strong message with a clear political content," the German chancellor, Angela Merkel, told reporters on Sunday after negotiations at the summit of the Group of Eight industrialised nations, or G8, in Saint Petersburg, Russia.
The leaders expressed their "deepening concern about the situation in the Middle East, in particular the rising civilian casualties on all sides and the damage to infrastructure," the statement read.
In their statement, the G8 leaders called for the Israeli soldiers abducted in Gaza and Lebanon to be released unharmed, the shelling of Israeli territory to end, Israeli military operations to cease and Israeli forces to withdraw early from Gaza, and for arrested Palestinian ministers and legislators to be released.
"We do not want to let terrorist forces and those who support them have the opportunity to create chaos in the Middle East," Merkel said. "Therefore we place value on clearly identifying the cause and effect of events.
"We are convinced that the government of Lebanon must be given all support and that the relevant UN resolutions regarding the south of Lebanon must also be implemented.
"We also demand that in addition to the UN activities, another observation and security mission is established. That must be worked out through the UN."
The UN Security Council adopted Resolution 1559 in September 2004, calling for all militias to be disarmed and for strict respect for Lebanon's sovereignty, territorial integrity, unity and political independence under Lebanese government authority.
Hezbollah has refused to disarm, saying it is a resistance movement.
It is widely viewed by the Lebanese as having liberated the southern part of the country when it pushed Israeli troops to withdraw in May 2000 after years of occupation.
The group, which is on the United States' terror list, has 14 MPs in parliament and two ministers in the cabinet.