Blast hits Tel Aviv bus
At least 18 people were injured when an explosion hit a bus in Tel Aviv Wednesday, police said.
A spokesperson for the Islamist group Hamas said it welcomed the bombing as a "natural response" to the ongoing Israeli bombardment of Gaza, but said it was not behind the attack.
In Israel, politicians, including deputy speaker of parliament Danny Danon, said the bombing meant Israel had no choice but to invade Gaza.
"It is time to declare war," Danon tweeted. "The time for restraint is over."
Police in Tel Aviv said they were seeking a suspected bomber and that one of the injured is in a "serious" condition.
Around 140 Palestinians have been killed in Israel's eight-day air and naval attack on Hamas-ruled Gaza, officials say. Gaza's health ministry says many children are among the dead.
Israel says it began its attack on the city of 1.7 million in response to a surge in rocket attacks from Gaza.
Palestinian rockets continued to hurtle toward Israeli towns and cities Wednesday, but most were knocked down by the sophisticated Iron Dome air defence system.
Israel says five people have been killed by Palestinian rockets in the last eight days.
A spokesman for Israeli Prime Minister Benjamin Netanyahu tweeted that a second bomb that did not explode had also been found on the bus in Tel Aviv.
An Israeli defence forces spokesman said on Twitter that Hamas members had celebrated on the streets of Gaza as news of the bus bombing broke.
The bombing comes amid frantic negotiations to end the violence.
US Secretary of State Hillary Clinton met Israeli Prime Minister Benjamin Netanyahu after flying into Jerusalem late Tuesday. Clinton was due to visit the West Bank and Cairo later Wednesday.
"It is essential to de-escalate the situation in Gaza," she said ahead of talks with Netanyahu. "The rocket attacks from terrorist organizations inside Gaza on Israeli cities and towns must end and a broader calm be restored."