Rishi Sunak met Metropolitan Police chief Sir Mark Rowley for talks on Tuesday after the violence in London on Armistice Day.
The meeting came after police made scores of arrests on Saturday, mainly of counter-protestors, as hundreds of thousands of people took part in a pro-Gaza march in the city centre.
Far-right activists clashed with police near the Cenotaph in Whitehall and in other parts of central London.
Some individuals involved in the pro-Palestinian march were also arrested, with reports of fireworks fired at police by one small group.
The Prime Minister's official spokesman said: "You heard from the Prime Minister at the weekend that the public rightly expect that the full force of the law is used to bear down on some of the shocking scenes of criminality that we saw at the weekend, whether it was EDL protestors or those seemingly supporting Hamas, a proscribed terrorist organisation."
New Home Secretary James Cleverly was also at the talks with the Met chief.
He was appointed after Suella Braverman was sacked as Home Secretary after a series of deeply controversial outbursts including branding the pro-Gaza demonstrations as "hate marches" and claiming that the Met Police was biased in the way it treats protests.
London Mayor Sadiq Khan accused Mrs Braverman of stoking community tensions, ahead of Armistice Day.
Mrs Braverman was also hit with a backlash after claiming that some people living on the streets of London or elsewhere do so out of a "lifestyle choice".
She was dismissed by Mr Sunak in a reshuffle on Monday which saw David Cameron made a peer and appointed Foreign Secretary.
Rightwing Tory MPs criticised the shake-up of the Prime Minister's top team which met for the first time in the Cabinet Room in Downing Street on Tuesday morning.
But the changes, including the sacking of Mrs Braverman, was welcomed by many MPs on the Left and in the Centre of the party.
Three men were arrested after racist abuse was shouted at pro-Palestine protesters at Waterloo station.
British Transport Police said on Monday that the men were detained "in connection with a racially aggravated altercation" after the protest was dispersed at around 5.30pm on Saturday.
A 57-year old from Surbiton, south west London; a 61-year old from West Molesey, Surrey; and a 33-year old from Christchurch, Dorset were taken into custody.
The arrests come after 145 people were detained by the Metropolitan Police during heated scenes involving Far-Right and pro-Palestine protesters at the weekend.
Of these, 91, including a large number of Far-Right protesters in Pimlico, were arrested to prevent a breach of the peace and released once the imminent threat of harm had ended.
So far eleven people have been charged with offences including assault on an emergency worker, criminal damage, racially aggravated assault and possession of an offensive weapon.
Nine police officers were injured as they prevented a violent crowd reaching the Cenotaph, in what was supposed to be a counter-protest as hundreds of thousands of people took part in a pro-ceasefire rally.
Police said that while the march did not see the sort of violence carried out by Far-Right groups, officers were investigating serious offences relating to antisemitism and hate crimes.
There were also clashes when pro-Palestine protesters gathered at Waterloo and Victoria stations.
Cabinet minister Michael Gove thanked police for getting him "home safely" after he was mobbed by demonstrators at Victoria.
