Washington: The United States will not tolerate any form of foreign interference in its elections, President Donald Trump said Wednesday after signing an executive order that initiates actions, including sanctions, against foreign entities who meddle or even attempt to interfere in American polls.

"Today, I took action to protect the integrity of the United States electoral system by signing an executive order to ensure that we can swiftly identify and punish any foreign interference in our elections. As I have made clear, the United States will not tolerate any form of foreign meddling in our elections", Trump said in a statement after he signed the executive order.

The executive order requires the intelligence community and other federal agencies to assess the extent of any foreign interference after every United States election. If the US determines that any foreign meddling has occurred, the executive order ensures a quick, forceful, and proportionate response, he said.

Specifically, the executive order authorises appropriate and meaningful sanctions some are full blocking sanctions, others are to be designed and calibrated in light of specific facts against any individual, foreign entity, or country that authorises, directs, sponsors, or otherwise supports foreign interference in a US election, he said.

It also directs the executive branch to develop a uniform process for assessing and determining foreign interference in United States elections.

"As we enter election season this fall, the American people can rest assured that we are working diligently to ensure that our democracy remains secure from foreign threats", Trump said.

Secretary of Homeland Security Kirstjen M Nielsen also said election security is national security and any attempt to interfere in the democratic institutions is unacceptable.

"By mandating the imposition of sanctions against any individual or entity that seeks to interfere in our elections, we are sending a clear signal that the US government will not tolerate interference of any kind and will use every tool at our disposal to protect our democratic process," she said.

The executive order does not name any particular country. However, in a conference call, Dan Coats, Director of National Intelligence identified Russia, China, Iran and N Korea having capabilities to do so.

"We have seen signs of not just Russia, but from China, of capabilities, potentially from Iran and even North Korea. It's more than Russia here that we're looking at," Coats said.

"We continue to look at that and will continue to look at that. We have not seen the intensity of what happened in 2016, but it's only a keyboard click away," he said.

However, the opposition Democrats were not satisfied with the executive order.

"The new executive order certainly does not absolve the Senate from passing much-needed legislation and funding to beef up our election security and prevent future attacks on our democracy from foreign adversaries," Senate Minority Leader Chuck Schumer said.

The steps outlined in the executive order are "far too little, too late," and they provide no resources to help states protect their elections against future attacks, said Committee on House Administration Ranking Member Robert Brady, Committee on Homeland Security Ranking Member Bennie Thompson, and Committee on Oversight and Government Reform Ranking Member Elijah Cummings.

"While the President appears to acknowledge that foreign actors will continue to attempt to interfere in our elections, he makes no mention of previous Russian attacks", they alleged.

Rather than issuing a weak executive order two years after these attacks, President Trump should have responded swiftly and strongly, they said.

"We need concrete actions that show the Trump Administration is sincere in wanting to protect American democracy from foreign interference. That means providing states with the funds they need, and pressing Republicans in Congress to pass legislation like the Election Security Act that makes meaningful improvements to our election infrastructure, the three Democrats said.