LONDON — Angered and dismayed by the downing of a Malaysian airliner over Ukraine, European leaders cast about for some form of joint response to the tragedy on Friday. But beyond calls for an international inquiry, they showed few signs of immediately following the United States in imposing harsher sanctions on Russia.

With sentiments ranging from shock to fury, political leaders across the globe urged a rapid, independent and international effort to investigate the crash, which killed 298 people and provoked accusations and counteraccusations about who brought the plane down.

Speaking to reporters in Berlin, Chancellor Angela Merkel of Germany, which has close economic ties with Moscow, said there were “many indications” that the Malaysian airliner “was shot down.” The Ukrainian government and its pro-Moscow separatist foes in eastern Ukraine, where the plane crashed, have blamed each other for bringing it down. American and Ukrainian officials say the jetliner was brought down by a Russian-made antiaircraft missile.

But Ms. Merkel declined to answer repeated questions about whether she would support tougher sanctions against President Vladimir V. Putin of Russia, beyond the more limited measures to which the European Union has already agreed. The United States imposed a new and tougher round of sanctions on Russian companies and business executives on Wednesday before the downing of the airliner on Thursday.