As fighting in the Gaza Strip entered its fifth day and Palestinian rockets landed deeper into Israel, travelers who had hoped to visit the Holy Land are starting to think twice.

But travel industry executives say there has not yet been a mass wave of cancellation.

A number of hotels in Israel, along with flagship airline El Al, have already seen some cancelations and believe the number will grow if the violence heads into a second week.

"There are minimal cancelations at this moment, but obviously it is an evolving situation," said a source in the Tourism Ministry, which has yet to offer official statistics.

Israel unleashed an intensive air campaign against the Gaza Strip on Wednesday with the stated intention of stemming Islamist militant rocket fire out of the coastal enclave.

Since the start of the conflagration, hundreds of missiles have been launched into Israel, with several speeding towards the commercial hub of Tel Aviv, which had previously been out of range of Gaza militants. Air raid sirens even sounded in Jerusalem on Friday for the first time in decades before a rocket landed nearby, in the West Bank.

Three Israelis were killed by a direct hit on their apartment building in the southern town of Kiryat Malachi on Thursday, but none of the longer-ranged salvoes struck populated areas or caused any injuries. However, the threat alone is taking a toll.

Start of a trend?

But the fighting comes when travel to Israel is low, after the High Holidays in September and early October that bring Jewish visitors, and before the start of the Christmas-New Year's period, which brings Christians and Jews alike. In the first 10 months of the year, some 3 million tourists came to Israel, an 8% increase over 2011. A spokeswoman for Fattal, Israel's biggest hotel chain, said a few bookings have already been canceled. "We see the start of a trend, but only in a few days will we be able to see where the overall trend is headed," she said, declining to give numbers.

Likewise, Jerusalem's American Colony hotel reported that some clients had pulled out of visits at the last minute.

An El Al spokeswoman said there have been a few cancelations "here and there" though nothing significant, while Delta and US Airways said some families of Israelis called up by the army had decided to delay travel plans.

The slowdown was not limited to Israel. Bethlehem, where the Church of the Nativity attracts Christian pilgrims from around the world, had lost nearly half its reservations due to the Israeli-Gazan violence.

"I think that the percentage of the cancelations has reached 40 to 50 percent until the end of November and for the next month," said Elias al Arja, head of the Arab association for hotels in the city.

Four cruise ships carrying 6,000 tourists chose not to dock in Israel due to the security situation, Israel Radio reported on Sunday. Some foreign airlines have decided to ferry their crews abroad rather than have them pass their overnight stays locally.

Flight patterns for flights to and from Tel Aviv's Ben-Gurion International Airport have been shifted north and east to free up air space for Israel's air force operating in Gaza, said one official in the aviation industry.