Amid speculation that a bipartisan deal is near, Republican negotiator tells Fox News 'I don't think we're that close to a deal'

Reports of an imminent deal over new gun controls were dismissed by a key Republican negotiator Sunday as senators struggled to find a middle way between calls for tougher regulations in the wake of the Newtown school shooting and fearsome resistance from the gun lobby.

The Senate Judiciary Committee convenes on Thursday to begin thrashing out positions over proposed legislation relating to the sale and manufacture of guns. Speculation is running high that a deal is in the offing between leading senators for a bipartisan bill that would extend FBI background checks to all gun sales as a means of weeding out criminal buyers or those with mental health problems.

Both the Washington Post and the New York Times reported on Sunday that a deal between four senators – two Democrats and two Republicans – over extending background checks was now close, and that the aim was to present a draft bill to the judiciary committee at its hearing on Thursday.

But Tom Coburn, the leading Republican senator in the group of four, poured cold water on the idea that a breakthrough was imminent. He told Fox News Sunday that agreement was still proving elusive: "I don't think we're that close to a deal," he said.

The sticking point appears to the question of record-keeping. Advocates of greater controls, led by the New York senator Chuck Schumer within the group of four, want to see background checks extended to all gun sales, beyond the current position where only purchases at licensed gun shops are subject to FBI monitoring.

Some 40% of all gun sales go through private dealers who are exempt from any federal review.

Schumer and other reformers want private sales, made at gun shows and through the internet, not only to be put through the FBI-maintained National Instant Criminal Background Check System (NICS), but they also want such sales to be recorded. That would make it easier for police to track the movement of illegal guns and ensure firearms aren't procured by people with mental health issues.

The idea of registering all gun sales is red rag to the pro-gun lobby. They see it as a first step towards a federal registry of all guns and gun owners in America which in turn would prepare the way for a government conspiracy to confiscate the weapons.

"There absolutely will not be record-keeping on legitimate, law-abiding gun owners," Coburn said.

The Senate is taking the lead in the debate over gun controls in the wake of the Connecticut shooting in December in which 20 children were killed in their classrooms in Sandy Hook elementary school. The Republican-controlled House of Representatives, where bipartisan agreement is likely to be even more difficult to achieve, is holding back until the Senate makes clear its intentions.

There are three separate strands of legislation currently being discussed by senators. The first is the extension of background checks which is seen as having the best chance of success, the stalemate over record-keeping notwithstanding.

A second strand that is also attracting support from both parties is the idea of clamping down on so-called "straw purchasers" – those who buy guns on behalf of criminals who could not pass a background check themselves.

The third strand is looking very perilous as it is staunchly opposed by most Republicans and many Democrats, including Harry Reid, the Democratic leader in the Senate. That is the idea, favoured by Obama, of reviving a federal ban on semi-automatic assault weapons that lapsed in 2004 as well as imposing an upper limit on the size of magazines that can be attached to guns.

Gun control advocates point out that many of the most horrific recent mass shootings – including Newtown, Aurora and Tucson – have involved such military-style firearms equipped with large-capacity magazines capable of firing – in the case of the Aurora cinema massacre – up to 100 rounds in a matter of minutes. But the gun rights lobby sees the proposed ban as a federal assault on the Second Amendment right to bear arms, and have vowed to oppose it to the end.