Turkish terror attack: US, Middle East need to deepen co-operation, says Hillary Clinton

She added that the attack only strengthens the resolve to defeat terrorism and radical jihadism around the world

Presumptive Democratic presidential nominee Hillary Clinton has said the terror attack in Turkey is a reminder that the US can't retreat from this part of the world and needs to deepen co-operation with allies in the Middle East and Europe to take on this threat.

"Today's attack in Istanbul only strengthens our resolve to defeat the forces of terrorism and radical jihadism around the world. And it reminds us that the United States cannot retreat," Clinton said in a statement yesterday.

"We must deepen our cooperation with our allies and partners in the Middle East and Europe to take on this threat," she said adding that such cooperation is essential to protecting homeland and keeping the country safe.

"Yet another terrorist attack, this time in Turkey. Will the world ever realise what is going on? So sad," Republican presumptive presidential nominee Donald Trump tweeted.

"We must do everything possible to keep this horrible terrorism outside the United States," Trump said.

In a statement, the Trump campaign said the terrorist threat has never been greater.

"Our enemies are brutal and ruthless and will do anything to murder those who do not bend to their will. We must take steps now to protect America from terrorists, and do everything in our power to improve our security to keep America safe," the Trump campaign said.

Former Republican presidential candidate and Florida Senator Marco Rubio said the US stands with ally Turkey in condemning this attack.

"We stand ready to assist them as we learn more about the perpetrators responsible for this," he said.

House Democratic Whip Steny Hoyer said the attack in Istanbul was a heinous assault on a key US ally, and the Turkish people should know with certainty that the American people stand in solidarity with them in this difficult hour.

"Whenever terrorists attack a major global transit point, as they did a few months ago in Brussels and again today in Istanbul, they seek to erect barriers of fear that divide the free nations of the world. But we will not be divided," Hoyer said.

"We will stand together to meet the challenge of groups like ISIS, which represent the antithesis of our most important values - democracy, individual freedom, and opportunity for all," he said.