WASHINGTON (Reuters) - The U.S. House of Representatives on Thursday approved a $68 billion increase in military spending next year with legislation that also provides money to start construction of President Donald Trump’s Mexican border wall. The bill increased spending on the U.S. capability to defend itself from foreign missile attacks amid growing concerns about North Korea’s increasing capacity to hit the United States with a nuclear-tipped missile after it successfully tested an intercontinental ballistic missile in July. The money for the wall is dwarfed by the $658.1 billion the bill would provide for the Defense Department, an increase of $68.1 billion above the fiscal year 2017 enacted level and $18.4 billion above Trump’s budget request.      The House voted 235-192 for the fiscal 2018 spending bill that would provide $1.6 billion for initial construction of a wall on the U.S.-Mexico border, which was a centerpiece of Trump’s 2016 presidential campaign. Democrats repeatedly have referred to any money for the wall as a “poison pill” and are likely to try to kill it in the Senate. Congress is up against an Oct. 1 deadline - the start of a new fiscal year - for either passing spending bills or temporarily extending funding at current-year levels to give negotiators more time to come to agreements. Funding for the wall was tucked into a wide-ranging national security appropriations bill at the last minute by Republican leadership, knowing that many House members who oppose the wall would not sink defense spending with a “no” vote. Trump has argued that a “big beautiful wall” was needed along the entire southwestern U.S. border and that Mexico would ultimately pay for its construction. Mexico has flatly refused to pay and in recent weeks Trump indicated that there could be portions of the border that are not conducive to a wall. Democrats and many Republicans in Congress have questioned the feasibility and effectiveness of a border wall, with immigration advocacy groups arguing that it would not stem the flow of illegal border crossings and would hurt U.S.-Mexico relations. In interviews in recent weeks with more than a half-dozen Republican senators from states that voted for Trump for president last November, only Ted Cruz of Texas embraced building the wall. Similarly, House Republicans representing districts along the U.S.-Mexico border have expressed opposition to the barrier, which could end up costing well over $21 billion. Representative Nita Lowey, the senior Democrat on the House Appropriations Committee, called the wall a “waste ... that experts confirm is unneeded and ineffective and cuts against our values as Americans.” Furthermore, Lowey noted that Pentagon funding would run into a technical problem as it breaches a cap on defense spending by $72 billion. If the bill became law, she said, it actually would “trigger across-the-board cuts of 13 percent to every defense account” in order to stay within the cap.      The beefed up defense spending would allow the Pentagon to continue military activities in Iraq, Afghanistan and other trouble spots and hire more troops while providing soldiers with a 2.4 percent pay raise. It also would allow the Pentagon to undertake a shopping spree with money to buy ships and submarines, aircraft, tanks and other big-ticket items.   The House-passed bill also includes an increase for America’s nuclear weapons stockpile managed by the Department of Energy, as well as for U.S. Capitol Police following a June 14 shooting that gravely wounded Republican Representative Steve Scalise.       A $825 million increase for the Missile Defense Agency to more than $8.6 billion is more than Trump asked for and includes additional boosters and missile silos for the main system that would defend against an ICBM attack, a program run by Boeing Co.  Missile defense would also gain 14 more THAAD interceptors made by Lockheed Martin Co. 