The United States on Wednesday condemned a Hizbullah-backed assault on the Syrian town of Qusayr, saying the party's involvement threatens Lebanon's stability.

A White House statement condemned the Syrian regime's attack on the town, "which has killed untold numbers of civilians and is causing tremendous humanitarian suffering.”

A suspicious letter addressed to the White House and "similar" to one sent to New York Mayor Michael Bloomberg that tested positive for ricin has been intercepted, the Secret Service said Thursday.

"The White House mail screening facility intercepted a letter addressed to the White House that were similar to letters previously addressed to Mayor Bloomberg in New York," Secret Service spokesman Edwin Donovan said.

Seeking to quell a growing scandal, President Barack Obama said Monday it would be "outrageous" if U.S. tax authorities targeted conservative groups fiercely opposed to his White House.

As he battled growing political woes, Obama also denied his White House had engaged in a cover-up to downplay the impact to his re-election campaign of the attack on the U.S. mission in Benghazi last year, which killed four Americans.

The West Wing of the White House was temporarily evacuated Saturday morning after a minor electrical problem set off a smoke alarm, a White House official said.

"Early this am, an electrical transformer near the West Wing malfunctioned and set off a smoke alarm in the West Wing. The transformer problem was quickly resolved.

The White House said Monday it was appalled by "horrific" reports of a new massacre in Syria after a watchdog group said over 100 people, many of them civilians, were killed in a town near Damascus.

"We are appalled by horrific reports that hundreds of Syrians were killed over the weekend in a Damascus suburb," White House spokesman Jay Carney said.

The United States said it was taking "all necessary precautions" after North Korea rang fresh alarms in an escalating crisis by moving a medium-range missile Thursday to its east coast.

Seoul's defense minister Kim Kwan-Jin said the missile could reach a "considerable distance" but not the U.S. mainland, telling lawmakers it "could be aimed at test-firing or military drills".

U.S. President Barack Obama on Thursday played down expectations for a Mideast peace breakthrough during his upcoming trip to Israel, telling American Jewish leaders that he won't be carrying a "grand peace plan" when he arrives in the region later this month.

Obama, in an hour-long private meeting at the White House, acknowledged that near-term prospects for peace are bleak, according to a person who attended the discussion. But the president said a deal with the Palestinians remains the only way for Israel to achieve long-term security.

The White House Friday said it had been motivated by shielding Syrian civilians, Israelis and its own security, when President Barack Obama nixed an administration plan to arm Syrian rebels.

Defense Secretary Leon Panetta said during a congressional hearing Thursday that he backed plans to arm and train vetted rebel groups fighting President Bashar Assad's forces, in an initiative also supported by former secretary of state Hillary Clinton and ex-CIA chief David Petraeus.

Defense Secretary Leon Panetta on Thursday acknowledged for the first time that the Pentagon had backed proposals to arm the Syrian opposition battling to oust President Bashar Assad.

The idea -- ultimately rejected -- was first floated by then-secretary of state Hillary Clinton, who met privately with David Petraeus, CIA chief at the time, in the summer of 2012 as fighting raged in Syria.

U.S. President Barack Obama does not plan to use his coming trip to Israel to advance new proposals to break open the deadlock in peace talks with the Palestinians, the White House said Wednesday.

Obama will visit Prime Minister Benjamin Netanyahu for the first time as president as soon as next month on a trip that also includes stops in the Palestinian territories and Jordan.