A pair of missile strikes from American drones into Pakistan’s North and South Waziristan Agencies have killed at least 20 people, and injured an unknown number of others. This marks the first cross-border attack by US forces since President Obama took office on Tuesday.

Three missiles were fired at a house and another nearby building in Zera, North Waziristan killing 10 people and injuring many others. At least five of those killed in this incident were described by Pakistani officials as “foreign militants.”

Later, two other missiles were fired at a house in Wana, South Waziristan, also killing at least ten people. The identities of those killed was not readily apparent.

President Obama was a long time advocate of strikes into Pakistani territory, but the Pakistani government, which has publicly protested against such attacks, had expressed hope that the new administration might halt the attacks. The drone strikes have killed hundreds of people over the past several months, both militants and civilians. The United States rarely publicly admits to the attacks, part of what some in the media have dubbed a “don’t-ask-don’t-tell” understanding between them and Pakistan’s civilian government.