US President Barack Obama has confirmed that unmanned drones regularly strike suspected militants in Pakistan's tribal areas.
Mr Obama called the strikes a "targeted focussed effort at people who are on a list of active terrorists".
The US does not routinely speak publicly about drone operations.
Mr Obama made his comments during an hour-long video "hangout" on Google's social network, Google+, which was also streamed live on YouTube.
More than 130,000 questions were submitted before the hangout began, and six people were invited to join the president online for the event. They were able to ask questions and seek follow-up answers from Mr Obama.
The event ended a week of social media engagement in the wake of Mr Obama's State of the Union address on 24 January.
Obama administration officials, including Vice-President Joe Biden, held Twitter "office hours" last week.
Asked about the use of drone strikes, which have increased in intensity during his presidency, he said "a lot of these strikes have been in the Fata", or Pakistan's Federally Administered Tribal Areas.
The strikes target "al-Qaeda suspects who are up in very tough terrain along the border between Afghanistan and Pakistan," Mr Obama added.
"For us to be able to get them in another way would involve probably a lot more intrusive military action than the ones we're already engaging in."
Few details are known about the covert US drone operation, which is run by the CIA and targets al-Qaeda and Taliban militants in the mountainous areas along the Afghan-Pakistan border.
According to the AFP news agency, 64 US missile strikes were reported in the area in 2011, down from 101 in 2010.
They often cause outrage in Pakistan, where many assert that the strikes cause indiscriminate civilian deaths and injuries.
Anti-American feeling flared in Pakistan in the wake of the US special operations mission that killed Osama Bin Laden in 2011.
While Mr Obama has participated in virtual town halls before on sites like Facebook and LinkedIn, the event on Monday marked his first use of the Google social site, which was launched in mid-2011.
He is not the first US politician to "hangout", though: presidential hopefuls Newt Gingrich and Mitt Romney held their own virtual events on Google in 2011.
Questions submitted to the hangout were voted on by participants but ultimately selected by Google's staff.
The president asked Jennifer Weddel, one of the video chat participants to send him her husband's resume.
Mrs Weddel's husband had been out of work for three years, despite having a background as an engineer.
Mr Obama said with high-tech work in demand, her husband "should be able to find something right away".
During the event, Mr Obama answered questions on the anti-piracy bills that have stalled in Congress, visas for highly-skilled workers when unemployment in the US remains high and the consolidation of government agencies.
In a previous town hall-style event hosted by Facebook, the White House was criticised for ignoring one of most popular questions: Mr Obama's stance on legalising marijuana.
He did not answer questions on drug policy in Monday's event.