The shootings at a school in Jonesboro, Arkansas, in which four students and a teacher were killed, will inevitably re-open the debate on gun control in the United States. Over the past six months there have been at least four similar shooting episodes at schools in the United States, where youngsters have turned on their fellow pupils with firearms. But as our US Affairs Analyst Jonathan Marcus explains, however shocked US public opinion may be, there is little likelihood of significant further restrictions on the availability of guns.

The debate on gun control in the United States has raged for over three decades. The US has the largest number of guns in private hands of any country in the world - some estimates put the arsenal available to ordinary Americans at some 200 million firearms, perhaps even higher.

For the powerful firearms lobby the ability of every citizen to bear arms is considered a constitutional right. The advocates of gun control insist that murder and violent crime will only be contained if access to firearms is dramatically curtailed.

The Jonesboro shootings will inevitably revive the national debate on gun control - but it is one where the battle lines are clearly drawn - powerful political forces are at work - and any significant change to the status quo is unlikely.

During his first term as President, Bill Clinton assisted gun control supporters in scoring two important victories - the so-called Brady Bill that required background checks on all those purchasing firearms and a ban on the sale or import of certain types of automatic weapons.

But further gun control measures have been stalled since the Republicans gained control of Congress.

Last October gun manufacturers agreed with the President to introduce child-proof locks on handguns - in 1994 nearly 200 children died from accidentally discharging weapons.