"The Brigades will decide the right moment and place to strike back with force against the criminal attacks of Israel," a statement from the armed group said.
The move came in the wake of the death of seven Palestinians, including three young children, killed while on a day at the beach in the Gaza Strip when they came under fire from Israeli artillery.
The strike
The deaths on the beachfront in the Sudania area of the narrow coastal territory raised the death toll from Israeli strikes to 14 in less than 24 hours. The other seven were killed in air raids, according to medical sources.
Around 35 other people were wounded in the firing off the coast of Gaza.
Medical sources said five of those killed at the beach were members of one family from Gaza. Children aged one, three and 10 died alongside their parents.
Terrified crying children who were injured in the attack were rushed to nearby hospitals in Jabaliya and Gaza City where they were visited by Palestinian Prime Minister, Ismail Haniya.
Immediate Inquiry
The Israeli military confirmed that the navy had fired onto the beach, but said it believed the deaths were caused by shelling, not by firing from the gunboats.
"The chief of staff has ordered an immediate investigation into the incident," a spokesman said.
"As of now it is clear that Israeli naval fire did not cause this incident. The possibility of land-based artillery fire is being examined. The IDF deeply regrets any harm caused to innocent civilians."
The army later announced that chief of staff Dan Halutz ordered a suspension to the bombardments as the inquiry was launched.
The deaths at Sudania capped an upsurge of Israeli attacks on the Gaza Strip which began with an overnight air strike which killed the leader of a hardline armed faction and three other militants.
A further three suspected militants were killed in a fresh round of air strikes which targeted a group behind a new series of rocket attacks.
President responds
Palestinian president Mahmud Abbas condemned what he called the "bloody massacres" in the Gaza Strip, and one of his top officials contacted Western governments to persuade them to help rein in the Israeli military.
"What the Israeli occupation forces are doing in the Gaza Strip constitutes a war of extermination and bloody massacres against our people," President Abbas said in a statement carried by the Palestinian official Wafa news agency.
The strikes came at a sensitive time for President Abbas as the moderate president prepared to announce a controversial referendum that calls for an end to attacks on Israel.
He is well aware that the deadly operations by the Israeli military inside Gaza will make it that much harder to secure backing for such a measure.
Chief Palestinian negotiator Saeb Erakat also slammed "this dangerous Israeli escalation in the Gaza Strip".
"I have made contacts with the US administration and the EU and asked them to intervene immediately to put an end to this dangerous escalation," said Mr Erakat.
Funeral
Tens of thousands of Palestinians had earlier attended the funeral in southern Gaza for the victims of the overnight air strike in which Jamal Abu Samhadana, head of the Popular Resistance Committees, was killed.
Many of the mourners in the town of Rafah, which borders Egypt, chanted calls for suicide bombings inside Israel to avenge the death of Abu Samhadana who had served as an advisor to the Hamas-led Palestinian government.