Details have been emerging of the suspected attempt to hijack an Israeli aircraft bound for the Turkish city of Istanbul on Sunday.

Authorities have stressed the man is thought to have acted alone

A man is said to have attempted to break in to the cockpit of the El Al flight and stab a stewardess with a pocket knife.

The suspect, a 23-year-old Israeli Arab named Tawfiq Fukra, has reportedly told Turkish police he wanted to divert the plane back to Tel Aviv and crash it into a building in an 11 September-like attack, according to Turkish media reports.

But he was quickly restrained by guards aboard the flight from Tel Aviv, and the plane landed safely at its destination with all 170 passengers unharmed.

The Israeli government said in a statement it was "to all appearances a terror attack".

Authorities have stressed that the man is thought to have acted alone and no organisation has come forward to claim responsibility for the alleged hijack attempt.

However the incident has raised questions as to how the man managed to breach El Al's well-known stringent security checks.

'Ran amok'

According to passenger accounts, Mr Fukra was travelling business class, and behaved strangely throughout the flight.

El Al has the tightest airline security in the world

They said he visited the toilet frequently throughout the flight and made one call on a mobile phone.

A few minutes after the plane began its descent, he reportedly lunged for the cockpit door, at which point a stewardess raised the alarm, causing two El Al security guards to come to her aid and overpower the man, who was carrying a small pocket knife.

"We heard people saying there was fighting and half a minute later it became clear that from row five or six a man ran amok towards the pilot's cabin, attacked a stewardess and tried to enter the cockpit," a passenger, identified as Menachem, told Israeli radio.

"We saw a stewardess running like crazy from the front of the place to the business section... she was terrified," he added.

After being pinned to the ground, the man reportedly professed his innocence, saying he was visiting Turkey to see a friend.

Tight security

Several passengers said the incident was over so quickly they only became aware of it when the captain appealed over the plane's intercom for calm.

El Al attacks

1968 flight from Rome hijacked 1970 hijack thwarted in mid air 1986 thwarted attempt to put a bomb on board a plane 1972 Japanese Red Army faction members opened fire at Tel Aviv airport 1985 Palestinians attacked El Al check in counters in Rome and Vienna killing 18

Once the plane landed in Istanbul the suspect was quickly taken away by Turkish police.

El Al has the tightest security of any airline in the world, even before the events of 11 September led to an overhaul of airline security.

It is renowned for its strict procedures, having undercover agents on every plane and armed guards at every ticket counter.

The only successful hijacking of an El Al plane was in 1968 when a flight from Rome was hijacked by members of the militant Popular Front for the Liberation of Palestine and forced to land in Algiers.

However the fact that a man reportedly armed with a knife managed to board an El Al plane is bound to prompt serious questions over security.