CAIRO, Sept 29 (Reuters) - U.S. national security adviser Jake Sullivan discussed securing "tangible and lasting improvements" in human rights with Egypt"s president and other top officials during a visit to Cairo on Wednesday, a senior U.S. official said. President Abdel Fattah al-Sisi and Sullivan also agreed to intensify cooperation over upcoming elections in Libya, and addressed regional issues ranging from the Grand Ethiopian Renaissance Dam (GERD) to the situation in Tunisia and reconstruction in the Gaza Strip, both sides said. Egypt"s role brokering a ceasefire in Gaza following 11 days of fighting between Hamas and Israel in May earned it recognition at a time it was struggling to strike a rapport with U.S. President Joe Biden"s administration amid differences on human rights. The Biden administration said this month it would withhold $130 million worth of military aid to Egypt until Cairo took specific steps on rights. Human rights groups that had called on the U.S. to block $300 in aid expressed disappointment. On Wednesday, Sullivan reaffirmed Biden"s commitment with Sisi to "a constructive dialogue on human rights", the senior administration official said. The delegations discussed "the importance the United States places on securing tangible and lasting improvements in human rights, and in this regard, specific steps in connection with U.S. security assistance for Egypt", the official added. A statement from Egypt"s presidency made no mention of human rights. Under Sisi there has been a far reaching crackdown on political dissent, which activists say has left tens of thousands jailed. Sisi denies there are political prisoners in Egypt and says the state is providing rights by promoting economic and social development. Sullivan arrived in Cairo after trips to Saudi Arabia and the United Arab Emirates and was accompanied by Brett McGurk, White House coordinator for the Middle East and North Africa. read more During talks, the U.S. and Egypt underscored shared visions on issues including "a return to constitutional order in Tunisia, and support for civilian-led transition in Sudan," the senior administration official said. Sisi stressed the importance of sticking to a plan to hold elections in Libya in December, according to Egypt"s presidency. The planned poll is part of a United Nations-led effort to reunify Libya after years of conflict and division, but faces steep challenges. read more