Prime Minister Tony Blair has called for tougher laws to tackle gun and knife crime as he campaigned in the Welsh assembly election.
Mr Blair later took a boat trip on a visit to Milford Haven
He urged people to accept that a minority of black youngsters were responsible for most of the recent violence.
Mr Blair said the ringleaders had to be "taken out of circulation".
On one of his last visits to Wales as premier, he spoke first in Cardiff and moved on to campaign in west Wales.
He gave a lecture in memory of James Callaghan, his predecessor as Labour prime minister, and backed plans for a statue to the former Cardiff MP.
Mr Blair said that although cities like Cardiff had seen a physical regeneration, there was now a need to significantly toughen laws to tackle gun and knife crimes among the minority.
"The black community - the vast majority of whom in these communities are decent, law-abiding people horrified at what is happening - need to be mobilised in denunciation of this gang culture that is killing innocent young black kids," he said.
"But we won't stop this by pretending it isn't young black kids doing it."
Mr Blair has said he will leave office by September and is expected to confirm when he will leave office after polling day on 3 May.
After 10 years in Downing Street, Tony Blair is poised to leave
There were only a few curious onlookers as Mr Blair arrived at Cardiff City Hall, although that swelled to about 50 when he left at lunchtime.
He then visited the Corus steelworks in Port Talbot before heading to Pembrokeshire for some election campaigning with Welsh Labour leader Rhodri Morgan.
Speaking in Milford Haven, the Mr Blair said investment in
Wales would be at risk if the Conservatives were allowed back into office.
He told BBC Wales: "I know for very obvious reasons people like yourself want
to go on about me but in the end this isn't an election about me.
"I'm coming to the end of my time as a Prime Minister.
"But it is an election about the future of Wales."
He warned that voters faced a straight choice between Labour and a "rag-bag
coalition" after 3 May.
Conservative shadow Welsh secretary Cheryl Gillan said her party was "delighted" Mr Blair was visiting to remind people "why after a decade of Labour it is so important to vote for change in May's assembly elections".
She said: "Tony Blair and (First Minister) Rhodri Morgan's legacy in Wales will be one of failure and broken promises.
"The reality is that Wales today is not getting the things that Tony Blair and Rhodri Morgan promised us."
Liberal Democrat MP Jenny Willott said: "Tony Blair has not been a great friend to Wales. His farewell tour may have now reached Cardiff but Wales will not be asking for an encore.
"From the war in Iraq to support for nuclear power, from forcing students into mortgage-style debts to treating Wales as a second-class nation, the Blair years will be seen as a missed opportunity."
Plaid Cymru said: "Every time Blair visits Wales it reminds people that 3 May is the last chance they will get to give him the send-off that he deserves.
"The people of Wales will never forgive him for taking us into an illegal war in Iraq. In the unlikely event that he wants to visit Wales again during the campaign we will willingly pay for his train ticket."
Plaid's leader, Ieuan Wyn Jones, was in Anglesey highlighting the party's promise to cut business rates for small firms.
He visited a farmer in Bodedern who has built a go-carting track to diversify the business after the foot and mouth outbreak.
Liberal Democrat assembly leader Mike German was on the other side of Anglesey, at Menai Bridge, launching the Lib Dem north Wales manifesto.
It includes proposals to pilot health "walk-in centres" in north Wales and develop Anglesey as an "economic opportunity area," focusing on green jobs and tourism.
Conservative assembly leader Nick Bourne spent the day in mid and south Wales campaigning in seats the party is targetting.
He joined local candidates in Brecon and Radnorshire, Cardiff North and the Vale of Glamorgan.