(CNN) -

The violent cycle of retribution and retaliation only seems to be worsening.

As militants fire volleys of rockets from Gaza, Israel is responding with waves of airstrikes.

As Hamas vows to make its enemy pay the price, Israel is calling up hundreds of recruits and strengthening its positions around Gaza.

Tensions between Palestinians and Israelis have always simmered in plain view, erupting periodically into deadly spasms.

Could it be happening again?

"I do not want to over-dramatize, but the last few hours may have been, God forbid, the tipping point," Ari Shavit, a prominent Israeli author and journalist, told CNN's Christiane Amanpour on Monday night.

"What we see is different sides who do not want escalation ... they are dragged into something that is becoming very violent, very dangerous."

'The blood is up'

Long-standing resentments have boiled over in recent weeks following the kidnapping of three Israeli teenagers in the West Bank, which Israel blamed on Hamas. The militant group praised the abductions but denied responsibility.

Israel responded by cracking down on Hamas operations in the West Bank, arresting hundreds of activists and conducting widespread searches of homes.

When the three teenagers' bodies were found last week in a field in the West Bank, anger erupted in Israel. Prime Minister Benjamin Netanyahu vowed that Hamas would pay.

The mood darkened further when a Palestinian teenager was abducted and killed in Jerusalem in what police say could be a revenge killing. The news sparked clashes between protesting Palestinian youths and Israeli security forces in Jerusalem.

Throughout that grim week, Israel and Hamas continued to trade fire across the Gaza border.

"You have got politics. The blood is up. You have got retaliation," said Aaron David Miller, a Middle East expert at the Woodrow Wilson International Center for Scholars.

'Clouds are getting dark'

The region has many depressing precedents when it comes to violence.

In recent decades, Palestinians launched two armed uprisings against Israel, known as Intifadas, that each went on for years.

In late 2008 and early 2009, Israel carried out airstrikes and then a ground offensive against Hamas in Gaza that killed hundreds of Palestinians.

In November 2012, the two sides fought a bloody eight-day conflict that ended in a cease-fire.

The region appears to be careering toward another confrontation.

"It's difficult to see how this stops. At what point does one of the sides say, 'You know what? Let's have a moment where we make a pre-emptive concession, we do some kind of peace talks,'" said CNN's Fareed Zakaria.

"That's not in the cards right now."

The Israeli military is nonetheless gathering its forces near the border with Gaza.

"They are talking about an escalation," said CNN's Ben Wedeman. "Perhaps not on the scale of November 2012 or the war at the end of 2008, beginning of 2009, but definitely there's a feeling that the clouds are getting dark over Gaza and things could get much worse."

On Tuesday, Israeli Defense Minister Moshe Ya'alon said the security operation against Hamas "will probably not end within several days." And the Israeli military was gathering its forces near the border with Gaza.

'I still think no'

There are reasons why violence may not engulf the whole region.

Although clashes flared in some areas of Jerusalem after the killing of the Palestinian teenager last week, the unrest doesn't so far appear to be spreading.

The Israeli daily newspaper Haaretz reported that "many East Jerusalem officials expect the turmoil to die down." It noted that West Bank cities have not joined the violent protests.

"Are we on the tipping point of a third Intifada? A major sustained escalation?" Miller asked in a conversation with CNN's Wolf Blitzer. "I still think no."