MOSCOW - The Kremlin on Thursday explained President Vladimir Putin's surprising decision to skip a planned high-profile visit to the United States next week by saying he needs to finish setting up his new government. Although this may sound like a lame excuse, it could actually be true. Or not.

Theories abound as to why Putin decided not to join other global leaders for a meeting outside Washington and to postpone a much-anticipated meeting with President Barack Obama.

Some suggest Putin wanted to avoid Western criticism over the police crackdown on protesters that began in earnest on the eve of his return to the presidency on Monday. Others speculate that the social tensions themselves are what is keeping him close to home.

But Putin's job swap with Dmitry Medvedev, the former president who is now prime minister, has created tensions of its own within Russia's ruling elite. Who will serve in the new Cabinet under Medvedev and what role will be played by other top Putin allies who object to being subordinate to Medvedev? No appointments have yet been made.

The White House announced on Wednesday that Medvedev will represent Russia at the summit meeting of the Group of Eight industrial nations at Camp David on May 18-19. Obama's first meeting with Putin as Russia's president is now due to take place at another global summit in Mexico on June 18-19.

The younger and seemingly more Western-leaning Medvedev has been Obama's partner in the U.S. effort to "reset" the strained relations between the two countries, while Putin, whose outlook was formed during the Cold War, has been more suspicious of U.S. intentions.

During the months before the March presidential election, Putin made criticism of the U.S. a central theme of his campaign. But now that he is back in the Kremlin he is expected to take a more pragmatic approach to relations with the West, especially in light of Russia's dire need for foreign investment.

Putin's return to the presidency has been soured by a series of protests that have been broken up by police, with hundreds of people detained. At least 20,000 people turned out for an opposition rally on the eve of his inauguration, far more than expected as the protest movement had appeared to be fizzling.

On Monday, as Putin was sworn in for a third term in a regal Kremlin ceremony, helmeted riot police chased demonstrators through the streets of Moscow to prevent them from protesting. Throughout the week, hundreds of protesters have continued to play a game of cat-and-mouse with police.

Some see Putin's cancellation of the Washington trip as an effort to avoid uncomfortable questions about the crackdown on dissent.

"He is not going to bring anything back from there," said Alexei Malashenko, a scholar with the Carnegie Moscow Center. "He will not come back as a winner, but will face criticism."

Malashenko said Putin's visit would send a sign of weakness after he accused the U.S. of funding the protest leaders.

"In the current context, Medvedev is a much more useful figure," he said. "He bears no responsibility, he is no longer the president, and everyone knows he's the eternal No. 2," Malashenko said.

Putin, however, has often relished an opportunity to take on his critics both at home and abroad.

At a summit with European Union leaders in Brussels in 2002, where he was criticized over the military campaign against Islamic militants in Chechnya, he famously struck back by telling those who supported the militants that he could arrange for them to be circumcised in such a way that "nothing will grow again."

"I don't think that Putin is scared of anything linked to politics," Arkady Dvorkovich, a presidential economic adviser who is Russia's envoy to the G-8, said in an interview on Ekho Moskvy radio. "This is laughable. These are just idle thoughts that have nothing to do with reality."

Olga Kryshtanovskaya, a prominent sociologist who studies the Russian political and business elite, said the opposition protests have contributed to infighting within the Kremlin.

"Things would have been easier if the situation in the country were calm," she said. "The government is being formed not for four, but for six years. The whole structure of power is being reformatted."

One question is what role, if any, will be given to Alexei Kudrin, the finance minister from 2000 to 2011, who sympathized with the protesters this winter and tried to mediate between them and Putin. He was fired after saying he would not work in a Cabinet led by Medvedev.

Igor Sechin, the powerful deputy prime minister who oversaw Russia's energy sector in Putin's Cabinet, also is considered unwilling to work under Medvedev. Both Sechin and Kudrin are longtime Putin allies.

Kryshtanovskaya said Putin was neither afraid of criticism nor interested in distancing Russia from the Group of Eight.

"For Russia, it is still an honour to be part of this small club of the most influential countries, and I don't think he decided to avoid contact with them due to diplomatic reasons," she said.