* Lavrov to meet Kerry in Berlin for talks
* Says Kerry understands seriousness of Syria crisis
* Russia says has promoted dialogue among Syrians
Russia will urge the United States on Tuesday to press the Syrian opposition to hold direct talks with Damascus, but fears "extremists" now have the upper hand among President Bashar al-Assad's opponents.
Foreign Minister Sergei Lavrov said before leaving for Berlin to meet Secretary of State John Kerry that the new U.S. top diplomat seemed to grasp the gravity of the crisis in Syria.
He said Washington should lean on the Syrian opposition to drop demands that Assad must leave power before talks can start.
"In our contacts with other countries that can influence the parties in Syria, we have noticed a growing understanding of the need to influence both the government and, first of all, the opposition so that they do not come up with unrealistic requests as preconditions for the start of dialogue," Lavrov said after talks with Dutch Foreign Minister Frans Timmermans.
"This is what we will discuss with John Kerry today. During our latest phone conversation I had the impression that he has an understanding of the acuteness of the situation in Syria."
Moscow and Washington have been at loggerheads over Syria, where 70,000 people have been killed in a nearly two-year-old conflict that began with a crackdown on street protests against Assad's rule.
Russia has been Assad's staunchest ally and, with China, blocked three U.N. Security Council resolutions aimed at mounting pressure on him to end the violence.
Washington has sided with the Syrian opposition in seeking Assad's removal from power.
Syrian Foreign Minister Walid al-Moualem said in Moscow on Monday that the government was ready for talks, but opposition leaders and rebel commanders insist Assad must go first.
Kerry responded dismissively to Moualem's offer, saying it was hard to understand how people having Scud missiles fired at them would take an offer of dialogue seriously. Syria denies using ballistic missiles in the fighting.
He also appeared to promise more concrete support to Assad's opponents, without saying whether the United States might rethink its earlier aversion to arming or training them.
"We are determined that the Syrian opposition is not going to be dangling in the wind," Kerry said in London on Monday.
Lavrov signalled that the prospects for direct talks in Syria had receded in the past few days.
"A few days ago it seemed that conditions for the sides to sit down for talks ... were getting clearer. There were calls in support of a quick start to dialogue," he said.
"But then came denials of such an approach. It seems extremists, who bet on a military solution to Syria's problems and block initiatives to start dialogue, have for now come to dominate in the ranks of the Syrian opposition, including in the so-called (Syrian) National Coalition," he added.
Western countries and some Arab states have accused Russia, a long-standing arms supplier to Damascus, of shielding Assad, whose Syrian opponents have bitterly denounced Russian policy.
Moscow has hit back by saying it has worked hard to try to persuade the two sides in Syria to start talks and accusing its Western allies of failing to do enough to support those efforts.
It also says support for the rebels plays into the hands of militant Islamists, a theme Assad himself often evokes.