NEW YORK - The Obama administration has accused Pakistan of illegally modifying the US-made missiles to expand its ability to hit land-based targets. Citing senior administration and Congressional officials, The New York Times made the accusation in a dispatch that also said the altered missiles posed a potential threat to India. The NYT said the charge came in late June through an unpublicised diplomatic protest to Prime Minister Yousuf Raza Gilani and other top officials. The accusation, made amid growing concerns about Pakistans increasingly rapid conventional and nuclear weapons development, triggered a new round of US-Pakistani tensions, the report added. Theres a concerted effort to get these guys to slow down, the newspaper quoted a senior administration official as saying. Their energies are misdirected, the official added. The accusation comes at a particularly delicate time, when the administration is asking Congress to approve $7.5 billion in aid to Pakistan over the next five years, the dispatch said. Washington, it added, is also pressing Pakistani military to focus its attentions on fighting the Taliban, rather than expanding its nuclear and conventional forces aimed at India. A senior Pakistani official, who spoke to the NYT on the condition of anonymity, also rejected the accusation, saying that the missile tested was developed by Pakistan, just as it had modified North Korean designs to build a range of land-based missiles that could strike India. He said Pakistan had taken the unusual step of agreeing to allow American officials to inspect the countrys Harpoon inventory to prove that it had not violated the law, a step that administration officials praised. US officials say the disputed weapon is a conventional one based on the Harpoon anti-ship missiles that were sold to Pakistan during the Reagan administration as a defensive weapon, the newspaper reported. The accusation stems from US intelligence agencies detection of a suspicious missile test on April 23 which was never announced by the Pakistanis and which appeared to give it a new offensive weapon, the newspaper said. The US military and intelligence officials suspect Pakistan of modifying the Harpoon sold to them in the 1980s, which would violate the Arms Control Export Act. The focus of our concern is that this is a potential unauthorised modification of a maritime anti-ship defensive capability to an offensive land-attack missile, another senior administration official told the NYT, speaking on condition of anonymity about classified information. When we have concerns, we act aggressively, the official added. Pakistan denied the charge and said it developed the missile, the NYT reported. It says some experts are also sceptical of the American claims. Robert Hewson, editor of Janes Air-Launched Weapons, a yearbook and Web-based data service, said the Harpoon missile did not have the necessary range for a land-attack missile, which would lend credibility to Pakistani claims that they are developing their own new missile. Moreover, he said, Pakistan already has more modern land-attack missiles that it developed itself or acquired from China. Theyre beyond the need to reverse-engineer old U.S. kit, Hewson said in a telephone interview. Theyre more sophisticated than that. Hewson said the ship-to-shore missile that Pakistan was testing was part of a concerted effort to develop an array of conventional missiles that could be fired from the air, land or sea to address Indias much more formidable conventional missile arsenal. Monitoring Desk adds: The charge of modifying the anti-ship Harpoon missiles is being based on the assumption that the US technology is now a part of the new generations of conventional and nuclear weapons Pakistan is developing. The New York Times says over the years, a total of 165 such missiles had been supplied; including 37 of the older-model delivered from 1985 to 1988, said Charles Taylor, a spokesman for the Defense Security Cooperation Agency. Citing American military and intelligence, the newspaper reports that Pakistan has modified the Harpoon anti-ship missiles supplied in 1980s, violating the Arms Control Export Act. The United States has also accused Pakistan of modifying American-made P-3C aircraft for land-attack missions, another violation of its law that the Obama administration has protested. The newspaper maintains whatever their origin, the missiles would be a significant new entry into arsenal against India enabling Pakistans small navy to strike targets on land, complementing the sizable land-based missile arsenal that Pakistan has developed. That, in turn, would be likely to spur another round of an arms race with the neighbour that Washington has been trying, unsuccessfully, to halt. The potential for proliferation and end-use violations are things we watch very closely, the NYT further quotes a US official. The most important point the latest dispute highlights, the NYT says, is the level of mistrust that remains between the United States and Pakistans military, as the Americans trying their best to get the military refocused on the internal threat, rather than India. And Pakistani officials have insisted that they are making that shift, but evidence negates their stance, the newspaper says. The newspaper points to rapid expansion strategic arsenals than any other nation, as Pakistan tested Babar medium-range cruise missile on May 6 during a visit to Washington by President Asif Ali Zardari, which was kept secret until three days after the meetings had ended to avoid upsetting the talks. Before Congress departed for its summer recess, administration officials briefed crucial legislators on the protest to Pakistan. The dispute has the potential to delay or possibly even derail the legislation to provide Pakistan with $7.5 billion in civilian aid over five years on which the lawmakers are scheduled to vote next month. Frederick Jones, a spokesman for Senator Kerry who is sponsoring the aid bill, declined to comment on the details of the dispute citing its classified nature but suggested that the pending multifaceted aid bill would clear Congress in a few weeks and would help cooperation between the two countries, the NYT reports. But he said, There have been irritants in the US-Pakistan relationship in the past and there will be in the future, noting that the pending legislation would provide President Obama with new tools to address troubling behaviour.