Germany sharply criticized Israel on Sunday for denying its development minister entry to the Gaza Strip to visit a humanitarian project co-funded by Berlin.
Foreign Minister Guido Westerwelle said he regretted Israel's decision, while Development Minister Dirk Niebel - who is on a four-day trip to Israel and the Palestinian territories -- said it was "a big diplomatic mistake".
Israeli Foreign Ministry spokesman Yigal Palmor said the move was part of Israel's long-standing policy on Gaza, which the Islamist group Hamas controls.
"We do not allow senior politicians into Gaza because Hamas will manipulate such visits to gain legitimacy," said Palmor.
Israel imposed a blockade on the Gaza Strip after Hamas seized control there from the rival Fatah-dominated Palestinian Authority in 2007.
The German Development Ministry said it had lobbied until the last minute for Niebel to be allowed into Gaza on Sunday, but had been informed on Saturday that it would not be possible.
Niebel told the German daily Leipziger Volkszeitung he was dismayed that Israel was "making it so difficult for even its truest friends to understand its behavior".
Israel has come under heavy international criticism since its forces boarded aid ships heading for Gaza last month and killed nine pro-Palestinian activists. Israel says its commandos had come under attack and were acting in self-defense.
About 1.5 million people live in Gaza, of whom about 1 million depend to some extent on regular supplies of United Nations and other foreign aid.
Israel announced last week it would ease its land blockade of Gaza, but Westerwelle said Germany and its EU partners would continue to push for a complete end to the blockade.
Israel said on Sunday it would soon start allowing into the enclave all types of goods except for weapons and materials that can be used to make them.