Alexei Druzhinin / Reuters/RIA Novosti/KremlinRussia’s President Vladimir Putin gestures as he chairs a government meeting at the Novo-Ogaryovo state residence outside Moscow.

President Vladimir Putin called for international access to the crash site of a Malaysian airliner in rebel-controlled eastern Ukraine, while the leaders of the U.S. and EU nations accused him of failing to back up his words with action and warned of additional sanctions when an EU panel convenes Tuesday.

In an address published on the Kremlin website early Monday morning, Putin also said that "Russia will do everything that depends on us for the conflict in eastern Ukraine to move from its current military phase into the phase of discussions at a negotiation table through peaceful and exclusively diplomatic means."

But Putin has been making similar statements for months, calling for the Ukrainian government and pro-Moscow insurgents to hold peace talks, and Western leaders have accused him of ensuring that the conflict rages on through his support of separatists.

"Elegant forms of words and fine communiques are no substitute for real action," British Prime Minister David Cameron said on his Facebook page Sunday.

"The weapons and fighters being funneled across the border between Russia and eastern Ukraine; the support to the militias; the half-truths, the bluster, the delays. They have to stop," Cameron said. "If President Vladimir Putin stops the support to the fighters in eastern Ukraine and allows the Ukrainian authorities to restore order, this crisis can be brought to an end."

Putin on Monday called for "all the people who are responsible for the security in the region to raise their accountability to their people and the people of the countries whose citizens perished in the accident."

But in the view of Western leaders, the list of people who are responsible for the security in the region starts with the Russian president.

U.S. officials also accused Putin of impeding international investigation of the crash in eastern Ukraine while denying that Russia might be responsible. The Organization for Security and Cooperation in Europe said Friday that its monitors had been blocked from accessing the site of the crash by "impolite and unprofessional" and apparently drunk gunmen.