By Saud Mehsud
DERA ISMAIL KHAN, Pakistan (Reuters) - A U.S. drone strike killed at least four suspected militants in northwest Pakistan on Monday, four intelligence officials said, the fourth such strike this year.
Two missiles hit a compound in the Shahi Khel area of Shawal Valley in North Waziristan, near the border with Afghanistan, the officials said.
"Through our local sources and intercepts, (we know) a drone fired two missiles at a compound in the Shawal area and killed four militants. The number of dead may go up," an intelligence official told Reuters.
The attack came a month after 134 school children were killed by Taliban insurgents, the worst single assault in the country's history.
Pakistan often publicly denounces drone strikes as an infringements of its sovereignty. But many say the military has given its tacit acceptance, pointing to a six-month halt in strikes last year while the government tried to negotiate peace with the Taliban.
Strikes resumed in June, days before the military launched an anti-Taliban operation in North Waziristan.
U.S. officials do not publicly speak about individual strikes.
Drone strikes in Pakistan have been gradually decreasing from a high in 2010, when there were 128.
Last year, 25 attacks in Pakistan killed up to 186 people, possibly including two civilians, according to the Bureau of Investigative Journalism, which tracks drone strike using media reports.
(Additional reporting by Hafiz Wazir in Wana, Javed Hussain in Parachinar and Haji Mujtaba in Bannu; Editing by Nick Macfie)