WASHINGTON (AFP) - Pakistan, under renewed US pressure since the death of Osama bin Laden, is stepping up its efforts to battle extremists and help stabilise Afghanistan, senior US Senator John Kerry said Tuesday. Some of them are important things that are very important to us strategically, but they are not appropriate to discuss publicly, said the Democratic lawmaker, who chairs the Senate Foreign Relations Committee. Kerry, newly returned from a whirlwind visit to both countries, said he had heard frustration from top Pakistani officials about the US raid that killed the Al-Qaeda leader, but had made clear Washington expects more from its ally. This relationship will not be measured by words or by communiques after meetings like the ones that I engaged in. It will only be measured by actions, said the Democratic lawmaker. They are concrete, they are precise, they are measurable and they are in many cases joint - and we will know precisely what is happening with them in very, very short order, he said. Im very, very confident about a number of those things having a major impact on the things we need to do, said Kerry, who promised to detail the new initiatives to his colleagues in a closed-door session expected next week. Kerry said high-level US-Pakistan talks that will begin very, very soon would touch on some larger issues and added that if they go well then US Secretary of State Hillary Clinton will decide when and if to visit Pakistan. The senator, who is sometimes discussed as a possible successor to Clinton, said he had no indication during his trip to Islamabad that high-level Pakistani officials had been complicit in hiding bin Laden. They admit things went wrong, they understand that mistakes were made, and theyre going to try to get at it. Im convinced that they want to find out because they want to hold those folks accountable, said Kerry. US lawmakers frustration was evident Tuesday as Kerrys committee quizzed President Barack Obamas former national security adviser, retired General Jim Jones, about prospects for improved US-Pakistan ties. You have a partner who can seem, as some have said, to be both firefighter and arsonist simultaneously, said Senator Richard Lugar, the top Republican on the panel and Obamas former foreign policy mentor. Jones repeatedly questioned the judgment of Pakistani leaders - saying that logic doesnt always play a dominant role in decision-making in Islamabad - but said he hoped they would forcefully cast their lot in with Washington. Im hopeful that at long last, cooler heads will prevail and logic will come into the equation and our colleagues in Pakistan will see the future with a little bit more of a strategic vision, said Jones. Pressed on whether Washington should freeze aid, Jones replied I would counsel against what might be a very tempting thing to do and warned against long-term consequences for US interests in the region. Kerry said Pakistans role would affect Obamas plans to start withdrawing US troops from Afghanistan in July and hand over security to Afghan forces in 2014, a deadline seen by some in Islamabad as Washington abandoning the region. We will pursue our policy in Afghanistan to the best of our ability no matter what, the senator said, but the Pakistanis hold the key to the fastest, least costly, most effective drawdown.