A number of Democrats in the US Senate are mounting a filbuster in an attempt to encourage their Republican counterparts to bring in gun control measures.

The marathon effort was commenced by Connecticut Senator Chris Murphy, who announced on Twitter:

I am prepared to stand on the Senate floor and talk about the need to prevent gun violence for as long as I can. I've had #Enough

— Chris Murphy (@ChrisMurphyCT) June 15, 2016

A number of other Democratic senators have since agreed to join Murphy, with their lengthy statements expected to continue long into the evening.

Politico reports that US senators were due to be debating a spending bill, but Democrats are attempting to add an amendment that would ban suspected terrorists from purchasing firearms.

Another gun control amendment is calling for universal background checks for gun purchasers, although Politico suggests any agreement on that is 'even less likely' than the other amendment.

The debate over gun control in the US has intensified following the worst mass shooting in US history, in which a man shot dead 49 people at a gay nightclub in Orlando.

Chris Murphy has been campaigning for more control in the aftermath of the Sandy Hook Elementary School shooting in his home state in 2012.

Speaking in the Senate earlier today, Murphy said: "I am prepared to stand on this floor and talk about the need for this body to come together on keeping terrorists away from getting guns, through those two measures, for frankly as long as I can.

"I know that we can come together on this issue [...] Having come through the experience of Newtown, I've had enough," he added.