So much for an emergency hotline. Next time Russian president Dmitry Medvedev wants to get in touch with his American counterpart, he has a new way to do it - if he can keep to 140 characters.
Medvedev, 44, has become the latest world leader to begin tweeting, after a tour of Twitter's San Francisco headquarters. His visit was also the first time the microblogging site had been visited by a head of state.
"Hello everyone, I'm at Twitter and sending my first message," Medvedev said in his inaugural tweet.
The Russian president, who met Ev Williams and Biz Stone, the site's co-founders, on his whistlestop tour, has registered two official Twitter accounts for the Kremlin - @kremlinrussia in Russian, and @kremlinrussia_e in English.
It was a busy day for the Russian president. He also found time to try out video conferencing at Cisco Systems as part of a fact-finding visit to US technology hub Silicon Valley.
Medvedev was clearly impressed with the technology. "This is amazing," he said in English, surrounded by Cisco executives. Medvedev has said Silicon Valley could be used as a possible model for Russia to follow.
"This experience is not definitive, but it is quite interesting," he said before he left Russia. The president has said he wants to build a high-tech hub outside Moscow, with tax breaks and special rules for investors.
"He [Medvedev] is remarkably open. I mean, business leaders go back and forth with him," said Cisco chief executive John Chambers. "It took me almost off guard."
Medvedev's whirlwind itinerary also includes visits to meet Steve Jobs, the Apple chief executive, and Russian web search firm Yandex.
And if the White House and 10 Downing Street are not sufficient to fulfil Medvedev's political Twitter-related desires, he will also be able to follow Israeli prime minister Binyamin Netanyahu and Hugo Chávez, the Venezuelan president.
But Medvedev probably needs to widen his net if he's to make the most of the Twitter experience: so far, he's only following Barack Obama and the White House.
