Pauline Hanson and Donald Trump have both received angry reactions to tweets posted just hours after attacks in London.
Senator Hanson was criticised on Twitter after posting "Stop Islamic immigration before it is too late. #auspol" within hours of the attacks.
"How sad it must be in your closed, scared little world Pauline," Ash London wrote in response.
"Using tragedy to push your agenda for hate is revolting," another wrote.
She received some support as well, however, with one user encouraging her to "Tellem (sic) Pauline", and another saying she was "100% correct".
It comes after she courted similar controversy in the wake of the Westminster Bridge attack earlier in the year, in which Ms Hanson appeared to accuse London's Mayor Sadiq Khan of being blaze towards the murders.
Senator Hanson's tweet on Sunday came in quick order after US President Donald Trump tweeted similar sentiments using the attacks to demand courts in his country reinstate his failed travel ban aimed at predominantly Muslim countries.
We need to be smart, vigilant and tough. We need the courts to give us back our rights. We need the Travel Ban as an extra level of safety!— Donald J. Trump (@realDonaldTrump) June 3, 2017
Whatever the United States can do to help out in London and the U. K., we will be there - WE ARE WITH YOU. GOD BLESS!— Donald J. Trump (@realDonaldTrump) June 3, 2017
British police rushed to two incidents in central London after a van ploughed into pedestrians on London Bridge and reports emerged of multiple stabbings in the nearby Borough Market area. Police said the attacks had been declared terrorist incidents.
"Whatever the United States can do to help out in London and the UK, we will be there - WE ARE WITH YOU. GOD BLESS!" Trump said in one of two tweets.
"We need to be smart, vigilant and tough. We need the courts to give us back our rights. We need the Travel Ban as an extra level of safety!" he said in the other.
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Trump's appeal for his travel ban followed his emergency request that the Supreme Court reinstate the executive order that would bar people entering the United States from six predominantly Muslim countries. It has been blocked by lower courts.
The US State Department condemned what it called "the cowardly attacks targeting innocent civilians" in a statement, and echoed Trump's readiness to provide any assistance that British authorities request.
"All Americans stand in solidarity with the people of the United Kingdom," State Department spokeswoman Heather Nauert said in the statement.
The department also said it was monitoring the situation in London closely, and advised American citizens in Britain to heed the advice of local authorities and maintain their security awareness.
Trump was briefed earlier about the London Bridge incident by his national security team, according to White House spokesman Sean Spicer, who said on Twitter that security officials would continue providing the president with updates.
Trump says the travel ban, a centrepiece of his 2016 campaign, is needed to protect Americans from terrorist attacks. Critics say his reasoning is flawed and assail the ban as discriminatory.
On Thursday, his legal team asked the high court to allow the March 6 executive order to take effect immediately despite being blocked by lower courts. The Supreme Court rarely grants emergency requests.