Trump faces backlash after invoking 9/11 in verbal assault on Michigan's Senate candidate

US President Donald Trump is facing a backlash after invoking 9/11 as part of a verbal assault on Abdul El-Sayed, the Democratic candidate for the US Senate in Michigan.

Speaking at a rally in the state on Sunday, Trump accused El-Sayed of being "a jihadist". He introduced as a guest speaker the father of a passenger who fought back against the 9/11 hijackers.

Trump also suggested that El-Sayed would "have to go through a metal detector before he's allowed to go into the Senate".

Critics condemned Trump's attack as Islamophobic. El-Sayed himself responded to Trump's decision to refer to him by his middle name, Mohamed, saying during a rally of his own: "I'll be Senator Mohamed to you, bro."

He also said: "They think that by pointing at my name and my faith, that somehow you're going to ignore the fact that you can't afford your gas or your groceries, can't see a doctor."

Appearing alongside him, Senator Bernie Sanders said: "The reason they are using Islamophobia against Abdul is because they have nothing to say about the real issues."

El-Sayed is taking on Republican candidate Mike Rogers on 3 November. The race is expected to be one of the closest in the midterm elections, and is proving to be particularly bitter.

The seat is considered to be one of just a handful that could decide the balance of power in Congress. It is currently held by the Democrats.

El-Sayed, a former public health official who was born in the US to Egyptian parents, will be the first Muslim elected to the US Senate if he wins the seat.

He has previously dismissed the various attacks made against him by both Trump and Rogers and denied any connection to extremist groups.

El-Sayed's opponents have sought to link him to the Muslim Brotherhood, an Islamist organisation that was founded in Egypt. Trump designated certain chapters of it as Foreign Terrorist Organisations earlier this year.

Some of the scrutiny of the affiliations of El-Sayed and his family members relates to their writings from more than a decade ago.

A social media post, external in 2012 by El-Sayed's half-sister, Eman Abdelhadi, appeared to refer to the movement, saying "my family has long been MB". El-Sayed's team have previously distanced him from other comments by Abdelhadi.

Critics have also pointed to an opinion piece El-Sayed wrote in Huffington Post in 2011, external about pro-democracy protesters in Egypt. In it, he acknowledged concerns that "supporting democracy in Egypt might allow the country to fall to the hands of the Muslim Brotherhood".

A year later he also allegedly signed an open letter by Egyptian Americans. In it, the group urged Mohamed Morsi, Egypt's first democratically elected president and a leader of the Muslim Brotherhood, to "purge the media and police" following the toppling of the authoritarian regime in the Arab Spring. This letter has not been discussed by El-Sayed.

El-Sayed has previously denied any connection to the Muslim Brotherhood and has stressed his loyalty to the United States. Asked recently at a town hall event whether he would disavow the organisation, he responded: "Absolutely."

Also in 2012, El-Sayed's current opponent Rogers, who was then a US representative and chairing the House Intelligence Committee, appeared to call for cautious engagement with the Muslim Brotherhood, telling Reuters, external: "Do I think there are moderate Muslim Brotherhood individuals we are going to have to reach out to and talk to? Yes but we are going to have to watch it carefully."