In the early morning hours of May 15, the cargo vessel Borkum stopped off the Spanish coast, lingering in the waters a short distance from Cartagena. At the port, protesters waved Palestinian flags and called on authorities to inspect the ship based on suspicions that it carried weapons bound for Israel.

Leftist members of the European Parliament sent a letter to Spanish President Pedro Sánchez requesting that the ship be prevented from docking. “Allowing a ship loaded with weapons destined for Israel is to allow the transit of arms to a country currently under investigation for genocide against the Palestinian people,” the group of nine MEPs warned.

Before the Spanish government could take a stand, the Borkum cancelled its planned stopover and continued to the Slovenian port of Koper. “We were right,” Inigo Errejon, the spokesperson for the hard-left Sumar party wrote on X, arguing that the Borkum’s decision to skip Cartagena confirmed the suspicions. But missed in the debate over whether the ship ought to be allowed to dock in Spain were the unlikely origins of the Borkum’s cargo.

According to documents seen by Al Jazeera, the ship contained explosives loaded in India and was en route to Israel’s port of Ashdod, some 30 kilometers from Gaza. Marine tracking sites show it departed Chennai in southeast India on April 2 and circumnavigated Africa to avoid transiting through the Red Sea, where Yemen’s Houthis have been attacking vessels in reprisal for Israel’s war.

The identification codes specified in the documentation, obtained unofficially by the Solidarity Network Against the Palestinian Occupation (RESCOP), suggest the Borkum contained 20 tonnes of rocket engines, 12.5 tonnes of rockets with explosive charges, 1,500kg (3,300 pounds) of explosive substances and 740kg (1,630 pounds) of charges and propellants for cannons.

A paragraph on confidentiality specified that all employees, consultants or other relevant parties were mandated that “under no circumstances” were they to name IMI Systems or Israel. IMI Systems, a defence firm, was bought by Elbit Systems, Israel’s largest weapons manufacturer, in 2018.

The commercial manager of the ship, the German company MLB Manfred Lauterjung Befrachtung, told Al Jazeera in a statement that “the vessel did not load any weapons or any other cargo for the destination Israel”.

A second cargo ship that had departed India was denied entry on May 21 to the port of Cartagena. Spanish newspaper El Pais reported that the Marianne Danica left from India’s port of Chennai and was en route to Israel’s port of Haifa with a cargo of 27 tonnes of explosives. Minister of Foreign Affairs Jose Manuel Albares confirmed in a news conference that the vessel was denied entry on the grounds that it was shipping military cargo to Israel.

These incidents add to mounting evidence that weapon parts from India, a country that has long advocated dialogue over military action in resolving conflicts, are quietly making their way to Israel, including during the ongoing months-long war in Gaza. A lack of transparency on India’s transfers helps them slip under the radar, say analysts.

Zain Hussain, a researcher at the Stockholm International Peace Research Institute (SIPRI), told Al Jazeera that “the lack of verifiable information makes it hard to determine whether transfers have taken place”.

But “collaboration between India and Israel has been happening for quite a few years now”, Hussain said, therefore “it’s not unfeasible that we may see some made-in-India components being used by Israel [in its war on Gaza]”. On June 6, in the aftermath of Israel’s bombing of a United Nations shelter at the Nuseirat refugee camp in Gaza, the Quds News Network released a video of the remains of a missile dropped by Israeli warplanes. Amid the tangled parts, a label clearly read: “Made in India.”