WASHINGTON - Amid rising concerns here about the turn of events in Pakistan, Democratic Senator John Kerry, chairman of the influential Senate Foreign Relations Committee, has called for U.S. support for sustaining democracy in the South Asian country. "Our objective, obviously, is to sustain the democracy," he said after talks with UN Secretary General Ban Ki-moon. "They're getting their feet under them right now, so we need to be helpful, we need to be supportive." General David Petraeus, the US military commander for the region, and Richard Holbrooke, the special envoy for Pakistan and Afghanistan, will brief lawmakers today on the Pakistan's political crisis, said Kerry. Pakistan's leaders "are working very, very hard to try to reach an agreement that will bring elements of the government together in unity and allow them to go forward," he said. Kerry spoke after Pakistan detained hundreds of activists Wednesday on the eve of a mass protest against the government, as demonstrators defied a ban on gatherings. "There's no surprise that it's difficult, because this is the first time in the history of Pakistan that you've had an election in which the presidency changed peacefully, and from an incumbent president to a new president," said Kerry. "There's an enormous economic challenge, there's a huge insurgent challenge, and the problems are complex," he said. "We're just going to continue to work through these obviously difficult transitional issues." In late February, Kerry called for an urgent boost in Western aid to Pakistan, warning that "time is running out" to keep the nuclear-armed US ally from slipping into chaos. Kerry, who wants to triple US non-military aid to Pakistan to 7.5 billion dollars over five years, also endorsed a new US think tank report calling for an immediate increase on top of that amounting to four to five billion dollars per year from Washington and its European partners.