Acting Prime Minister Ehud Olmert said Friday that the international community must maintain a united front against Hamas. "We have to retain the international front that Israel has built up over the principles we have set out," Olmert told members of his Kadima Party during a meeting Friday. Olmert spoke as Hamas' political leader, Khaled Mashaal, arrived in Moscow for talks with the Russian government. Olmert said Russia might limit its contacts with Hamas in the future. "In recent days, I received messages from Russian President (Vladimir) Putin, which talk about restrictions of their contacts with Hamas and support the principles we laid before the Palestinians and which have the support of the Quartet," Olmert said. Russian officials said they planned to use their meetings with Hamas to pressure the group to accept the international demands - to renounce violence and recognize Israel's right to exist - but Mashaal said Friday his group had no plans to recognize Israel. Olmert also said that Israel continued raids on terrorist groups in Palestinian areas to prevent attacks on Israel. "We are prepared everywhere where is the slightest danger of terrorist attacks," he said. "We have been pursuing all the ticking time bombs, which in recent weeks have stopped ticking because we prevented their activities." The Hamas delegation arrived in Moscow on Friday for three days of talks aimed at denting the group's international isolation. Immediately upon arriving in Russia, Hamas senior official Muhammed Nazal said that "the subject of recognizing Israel is not open for discussion." Shortly following the delegates' arrival, Putin indicated that he would not meet with the delegation as was originially planned. Foreign Minister Sergey Lavrov was scheduled to receive Hamas' exiled political leader, Khaled Mashaal, in what will be Hamas' highest-profile foreign visit. The Hamas delegation is set to have talks with Lavrov's deputy, Alexander Saltanov, as well as Russian lawmakers, and meet Russian Orthodox Patriarch Alexy II. Russia's invitation, extended by President Vladimir Putin, was the first crack in an international front against Hamas, listed as a terror organization the European Union and United States. Hamas has sent dozens of suicide bombers to explode in Israel, killed hundreds of Israelis, and does not accept the presence of a Jewish state in the Middle East. "Our trip to Moscow opens new prospects for peace in the Middle East," Mashaal said in an interview Thursday with NTV television in Damascus, Syria. "Our people want simple things: to be free and to have sovereignty. All this is impossible without an end to the occupation," said Mashaal. He declined to comment on the question of recognizing Israel. After arriving in Moscow, Mashaal accused Israel of blocking the Mideast peace process and said that Israeli "occupation" of the Palestinian lands will top the agenda in Moscow talks, the Russian news agencies reported. "We expect an exchange of opinions to take place and hope that nobody will put forward any conditions," Mashaal said, according to Interfax. Russia's special Middle East envoy, Alexander Kalugin, said the aim of the talks was not to dictate conditions to Hamas but to use persuasion. "We're not going to put forward demands. We'll seek to convince them that now is the time to take responsible decisions. If you come to power and form a government, you must understand you are assuming a great responsibility," said Kalugin in an interview with NTV. Russian analysts were skeptical of Moscow's ability to persuade Hamas. They predicted that the talks - being led Friday and Saturday by Mashaal and Russian Deputy Foreign Minister Alexander Saltanov - would lead nowhere. "Hamas won't listen to Russia because Moscow has no real levers of influence over them," said Fyodor Lukyanov, editor of the foreign policy magazine Russia in Global Affairs. "This is not the time of the Soviet Union, when we had real clout in the region." Russian President Vladimir Putin's invitation to Hamas last month was the latest bid by Moscow to invigorate its role in Middle East peacemaking. Moscow, which was a major player in the Middle East during the Soviet period when it provided aid to several Arab countries, belongs to the so-called Quartet of Middle East mediators alongside the United States, the European Union and United Nations. But Lukyanov said Russia did not provide significant aid any more, despite its oil wealth, and said only the United States had real influence in the Middle East. "These talks won't lead anywhere, but ultimately, the Americans may decide to get involved. And if Hamas is going to listen to anyone, it will be to them," he said.