Warning that cyberattacks pose a danger to U.S. security, President Barack Obama signed an executive order on Tuesday designed to better protect critical infrastructure from computer hackers.

Obama, in his annual State of the Union speech to a joint session of the U.S. Congress, said the United States is facing a "rapidly growing threat from cyberattacks."

The United States will help its allies confront an evolving al-Qaida threat and be more transparent with the American people in the fight against terror groups, President Barack Obama said Tuesday.

Al-Qaida was now a "shadow" of the group that was behind the September 11, 2001 attacks on the U.S., Obama said in his annual State of the Union address.

U.S. intelligence agencies believe North Korea "probably" conducted an underground nuclear test with a yield of several kilotons, the office of the Director of National Intelligence said Tuesday.

"The explosion yield was approximately several kilotons. Analysis of the event continues," the office said in a statement, confirming the blast had taken place in the area of North Korea's Punggye-ri nuclear test site.

U.S. President Barack Obama will announce in his State of the Union address Tuesday that he will pull 34,000 U.S. troops home from Afghanistan in the next year, a source familiar with his speech said.

The move will effectively halve the size of the current 66,000 strong U.S. force in Afghanistan, ahead of a final withdrawal of most foreign combat troops by the end of 2014.

Thailand said Tuesday that it had tightened security around the U.S. consulate in the northern city of Chiang Mai in response to warnings of a possible terrorist threat.

Prime Minister Yingluck Shinawatra said she had "instructed security officials to step up security protection" at the diplomatic facility.

Several Syrian gasoline trucks have reportedly headed to Damascus after filling their tankers in Lebanon, media reports said on Tuesday, pointing out that two trucks came under fire in the norther city of Tripoli.

The Energy Ministry has meanwhile denied the claims.

The Pakistani Taliban have included a Briton and an American in a slideshow of fighters killed in battle that also eulogizes al-Qaida mastermind Osama bin Laden.

According to the U.S. monitoring service SITE, the 12-minute, 56-second video was posted on jihadist websites on February 6 and was prepared by Umar Studio, the media wing of Pakistan's umbrella Tehreek-e-Taliban (TTP) faction.

A shooting erupted at a courthouse in Wilmington, Delaware Monday, leaving three people dead, including a gunman, police said.

"I can confirm a shooting at 8 am. Two civilians, females, were killed, two capital officers were shot. The gunman is dead inside the lobby," a police spokesman said at a news conference.

Several powerful tornadoes ripped through the southern U.S. states of Mississippi and Alabama injuring at least 60 people and destroying hundreds of homes at the weekend, emergency officials said Monday.

The city of Hattiesburg in Mississippi's Forrest County bore the brunt of the storms, with heavy rain continuing to lash the region and create a risk of flooding.

The head of Syria's opposition coalition, Ahmed Moaz al-Khatib, said Monday he had received "no clear response" from the regime of President Bashar Assad over his offer of dialogue.

Khatib said in late January he was prepared to hold direct talks with regime representatives who did not have "blood on their hands," and so long as the discussions addressed replacing Assad.