U.S. oil and gas producers increased drilling activity the most since April 2014 after OPEC agreed to its first production cut in eight years last month. The total number of rigs targeting the energy resources rose by 27 to 624 in the week ended Friday, according to Baker Hughes Inc. data. Crude prices rose to a 16-month high on Monday, prompting American firms to expand drilling after idling more than 1,000 oil rigs last year.